MPG out of a T18/T19 or NP435

67StockBlue · Post #1 by **67StockBlue** » Mon Nov 25, 2013 2:43 pm

Black Friday is next week, so while she gets the day for shopping I am taking the next day to hit the junk yards. :wink:

Anyways, just getting going on this build and am excited! I had a 65 Mustang with 200 inline 6 a few years back and loved it.

I recently picked up a 70 F100 shortbed with a C6 behind a tired 300. It starts shaking and screaming on the freeway around 55. It came with a front disc brake conversion, power steering (thompson pump), and an A/C unit. My goal is to make a good daily driver out of it with at least 20 MPG and able to do 75 to 80 on the freeway. I plan to start by putting in a T18 or NP435, then swap the engine to a 240 and gear the back end to 2.75 to 3.00. Is this just wishful thinking even with the proper tuning?

Is there a better manual trans to put in it? Is the M5OD going to suit me better? I like the idea of the 4 speeds because they have the reputation of being easy to work on and can last for years. The Mazda 5 speed has some mixed reviews though most are good. Is it fairly straight forward to rebuild? I won't be doing much pulling or hauling with it. Helping friends move here and there will probably be the most of it.

Any thoughts will be greatly appreciated. I am still learning the ins and outs with this truck and want to build it good and pass it down to the kids.

Respectfully,
Linwood

blmhawkeye · Post #2 by **blmhawkeye** » Mon Nov 25, 2013 3:01 pm

My buddy has his 86 shortbed with a 300/t18 and 2.75 rear end. carter 1 barrel and duraspark ignition. when he drives it 55-60 he gets around 21 mpg on freeway. he isnt able tp get the truck faster than 75 with his set up. he gets around 13-14 at the speed. The real problem your facing is aerodynamics for getting good fuel mileage. their was a thread posted recently that showed that once you started going faster than 55 that air resistance jumped exponentially as you went faster.

herosandwich · Post #3 by **herosandwich** » Tue Nov 26, 2013 10:19 pm

just out of curiosity, how big were the wheels on that truck? 15's?

Post #4 by **CoupeBoy** » Wed Nov 27, 2013 11:10 am

subscribing. I have a '65 reg cab/short bed that originally had a 240/3on the tree, it has a 302/C4 in it now. I'd like to switch it back some day. I have a 300 and a 240 and a ZF5 speed from a '94 F250 (4.9L). I'd also like to hit around the 20mpg mark, but realistically I know I never will. My normal highway speeds are 75-80mph. :rolflmao:

I was planning on going as minimalist as possible, upgrading to non-power front disc brakes move the gas tank out of the cab and under the box, lowering the frame as soon as possible. The body on my truck is a tad rusty so I have given more than a passing though about channeling the body down over the frame as much as possible. Wind resistance and speed are my enemies..

oki, now back to your topic, what induction do you think you are going to use? I'll have to go research but I don't think either the T18 or NP435 has synchronized low gear a T19 does. Personally I'm a fan of 1:1 final gear ratio through the transmission. With an overdrive you have additional drag/friction from the extra gears.

like I said.. subscribed. And if you haven't looked it up yet, you should check up posts from LazyJW. He purpose built a motor for trying to achieve max MPG.

-ron

Post #5 by **80broncoman** » Wed Nov 27, 2013 11:52 am

CoupeBoy wrote:subscribing. I have a '65 reg cab/short bed that originally had a 240/3on the tree, it has a 302/C4 in it now. I'd like to switch it back some day. I have a 300 and a 240 and a ZF5 speed from a '94 F250 (4.9L). I'd also like to hit around the 20mpg mark, but realistically I know I never will. My normal highway speeds are 75-80mph.

I was planning on going as minimalist as possible, upgrading to non-power front disc brakes move the gas tank out of the cab and under the box, lowering the frame as soon as possible. The body on my truck is a tad rusty so I have given more than a passing though about channeling the body down over the frame as much as possible. Wind resistance and speed are my enemies..

oki, now back to your topic, what induction do you think you are going to use? I'll have to go research but I don't think either the T18 or NP435 has synchronized low gear a T19 does. Personally I'm a fan of 1:1 final gear ratio through the transmission. With an overdrive you have additional drag/friction from the extra gears.

like I said.. subscribed. And if you haven't looked it up yet, you should check up posts from LazyJW. He purpose built a motor for trying to achieve max MPG.

-ron

I see your point about the 1:1 top gear in the trans Vs having a overdrive. If it was a large(r) trcuk trans I can see it being a issue but the smaller the trans the less of the OD being a drag.
If your truck is NOT going to be used as a truck at all and your engine is mild , you could use a T5 It take s VERY little HP to turn one of those transmissions.Next us would be the "MAZDOG" 5 speed that was used in the 1987? and up F150s.
Both the Mazda and T5s tak ATF If I remember right as lube.
(I typed the above before I saw you had a ZF5 trans)
The ZF 5 speed is not as bad on drag as you think since you have one I'd use it. I've been inside a ZF5 and it looked to be all bearings and no bushings where it matters. other then the gears set having more mass to get moving I'd think it hardly any different than a Mazda 5 speed.

I think you'll get your 20 mpg target,....just not at 75-80 MPH
My fathers old 95 F150 2WD 300EFI/Madzda 2.73 got 20MPH at 60-65MPH on steady state trips, one with me driving it no less.

BIG 6 farmer · Post #6 by **BIG 6 farmer** » Wed Nov 27, 2013 1:25 pm

The mazda 5 speed is a good Trans. Just that 1st & reverse, wrong gear ratio for a Truck. A 3.55 rear axle, with a 29-30 inch rear tire works well. :thumbup:

Nothing against a T5, but think I read the Mazda has a higher torque rating? :hmmm:

Mazda 5 speed cheap & easy to come by... A lot of abused, wore out T5s out there. And not cheap. The 5.0 Mustang boys, eat them for lunch. :nod:

The T18/19 or NP435, with a 3.00-2.75 good choice with a 300. A 240 wont pull that too well.

Post #7 by **CoupeBoy** » Wed Nov 27, 2013 2:13 pm

FWIW, I've got a M5OD transmission and transfercase also, sitting on the shop floor. I had considered putting it into my SWB stepside for a fun toy. I thought it would work nicely with the light vehicle weight. But then I'd have to find a front axle and I really don't need another 4wd in the fleet (both my wife and my Daily drivers are 4wd and I have a spare 4wd for farm use) Could be fun, maybe I could build it with a 4wd transmission/transfer case and never upgrade the front axle... :hmmm:

(nah!)

guhfluh · Post #8 by **guhfluh** » Wed Nov 27, 2013 5:04 pm

I answered your same question on fordification.com, but I'll answer here too for others benefit.

If you want to swap to a manual, the easy and cheap route is using a T-19 that has the 4.xx 1st gear ratio and using a 2.7-3.0 rear gear. It gets the rpm down equivalent to an OD trans and has decent gear splits. The 240 might struggle a little with less gear splits than a 5spd but a 300 will handle it pretty easily.

Swapping an auto to hydraulic slave manual is a good amount of work though, and I'd opt for an AOD swap to add an overdrive and lockup converter for better mileage and drivability without all the headache of a manual swap and probably a little less expensive too.

blmhawkeye · Post #9 by **blmhawkeye** » Thu Nov 28, 2013 12:55 am

herosandwich wrote:just out of curiosity, how big were the wheels on that truck? 15's?

Yes, 235/75/15s to be exact

Post **#10** by **Lazy JW** » Thu Nov 28, 2013 3:13 pm

I have an 81 F-150 with a 300 T-18 combination and a 2.75 differential. Stock Carter YF and stock single exhaust.

With my TorqueMotor (basically a stock 300 using a shorter-than-stock camshaft) it averaged just over 19 mpg for 60,000 mile on my 44 mile (one way) commute to work over a three year period in northern Idaho..

This is a legitimate AVERAGE, not a one-time mileage check. This includes winter, summer, any and all idling time, etc. as I tallied every gallon of gas and every mile driven.

This is a standard long bed pickup with no topper or bed cover. I seriously doubt that I left much on the table other than air drag.
Joe

arse_sidewards · Post **#11** by **arse_sidewards** » Fri Nov 29, 2013 9:12 pm

Another transmission to consider is the Clark 280vo. It weighs over 200lb and with an adapter plate and ring it should fit an FMX bellhousing, but it's got a .85OD. I still haven't figured out how the the clutch, flywheel or slave cylinder would be set up. I haven't got that far

(now for a slightly more useful contribution)
I'm getting 15-18.something MPG depending on highway/4low. My truck is lifted 3" in front, missing the air dam and has enough rake that the windshield wipers don't push down hard enough to be useful above 50mph. I'm running a single-cab longbed 4x4 with the E4OD, 3.08 gears and 31s. I've got manual steering, no smog pump or EGR and I'm running an electric fan that only comes on when I'm having fun in 4x4. My commute often includes a red light into a 1/8-1/4 mile of WOT. The rest of it is from 45-60 mph (do the math, that speed sucks) with some 70+ highway. I almost never see above 10 on the vac gauge in 4th gear unless I'm above 70 mph or coasting.

Hopefully that info helps someone.

If I can get 14mpg with that situation I could be getting 20+ if I fixed the aerodynamic issues (need a shorter driveshaft before I can lose height in the rear) and could cruise in a better RPM range. Eventually I plan on swapping in a NP435. I'll need to increase tire size or I'd be doing 2000RPM+ all the time on the highway. On a related note, what's the highest RPM the stock 300 can comfortably sustain indefinitely or for as long as it takes to burn 40 gallons of gas?

Post **#12** by **THE FRENCHTOWN FLYER** » Fri Nov 29, 2013 9:52 pm

arse_sidewards wrote:... what's the highest RPM the stock 300 can comfortably sustain indefinitely or for as long as it takes to burn 40 gallons of gas?

probably around 5000, which will probably put you somewhere around 140 mph, if you can find a mineshaft that deep

arse_sidewards · Post **#13** by **arse_sidewards** » Fri Nov 29, 2013 10:14 pm

So I can swap in a NP435, go 4.10 (skip the 35" tires, they kill axles anyway) and cruise the highway doing 3500 RPM on for hours and as long as my cooling and oil hold up I won't put pistons in orbit? I find this kind of hard to believe. I always thought the six didn't like anything more than diesel revs. The only thing that's been keeping me from swapping transmissions is that I'd need to get bigger tires to offset the lack of OD but if I can cruise at 2500-3500+ RPM as long as I'm willing to pay for the gas then that makes things easy.

5000rpm in my truck in 4th with the converter locked should be 210 mph. Maybe I could pull that off if lowered my truck, cut the roof and windshield and wore a motorcycle helmet for better aerodynamics. If I started with full tanks and had a 90mph tailwind I could probably hit 210 before I run out of fuel.

Post **#14** by **THE FRENCHTOWN FLYER** » Fri Nov 29, 2013 10:37 pm

arse_sidewards wrote: I find this kind of hard to believe. I always thought the six didn't like anything more than diesel revs.

Why would it be any less robust than a V8 with an equivalent stroke, say a 400M or a big block Chevy? It may have a hawrable volumetric efficiency at 5K because of the suckie manifolding but it will stay together at that steady sustained speed.

arse_sidewards · Post **#15** by **arse_sidewards** » Fri Nov 29, 2013 11:24 pm

THE FRENCHTOWN FLYER wrote:
arse_sidewards wrote: I find this kind of hard to believe. I always thought the six didn't like anything more than diesel revs.

Why would it be any less robust than a V8 with an equivalent stroke, say a 400M or a big block Chevy? It may have a hawrable volumetric efficiency at 5K because of the suckie manifolding but it will stay together at that steady sustained speed.

I guess that makes perfect sense, I just never thought of the 300 compared to other engines designed around the same time.

motzingg · Post **#16** by **motzingg** » Mon Dec 02, 2013 12:28 pm

THE FRENCHTOWN FLYER wrote:
arse_sidewards wrote:... what's the highest RPM the stock 300 can comfortably sustain indefinitely or for as long as it takes to burn 40 gallons of gas?

probably around 5000, which will probably put you somewhere around 140 mph, if you can find a mineshaft that deep

Ha HAAAA

Post **#17** by **THE FRENCHTOWN FLYER** » Mon Dec 02, 2013 8:32 pm

I guess I need to qualify my answer a bit. The exhaust valve rotators tend to fail at sustained high speeds. If you are building an engine to run at sustained high speeds you should substitute INTAKE retainers on the exhaust valves, with, of course some springs that give the correct load (about 71 - 75 lbs) at the installed height.

arse_sidewards · Post **#18** by **arse_sidewards** » Mon Dec 02, 2013 9:13 pm

THE FRENCHTOWN FLYER wrote:I guess I need to qualify my answer a bit. The exhaust valve rotators tend to fail at sustained high speeds. If you are building an engine to run at sustained high speeds you should substitute INTAKE retainers on the exhaust valves, with, of course some springs that give the correct load (about 71 - 75 lbs) at the installed height.

I'm not building an engine for sustained high rpm operation. I'm trying to decide if I can swap a NP-435 in for my E4OD with 3.05s and 31s and not be over revving to sustain 90mph for as long as I have fuel. my future plans include 37" Humvee takeoffs (haven't decided which tread pattern) and 3/4 ton axles. I've got a 4.10 and 3.54 3rd member and I need to know which ratio I should be looking for gears to match. I'm thinking that I'll striaght swap the 4spd and run 31s until I can swap to 37s and 3.54 gears at the same time.

300 6 JEEP · Post **#19** by **300 6 JEEP** » Wed Dec 04, 2013 10:48 am

arse_sidewards wrote:
THE FRENCHTOWN FLYER wrote:I guess I need to qualify my answer a bit. The exhaust valve rotators tend to fail at sustained high speeds. If you are building an engine to run at sustained high speeds you should substitute INTAKE retainers on the exhaust valves, with, of course some springs that give the correct load (about 71 - 75 lbs) at the installed height.

I'm not building an engine for sustained high rpm operation. I'm trying to decide if I can swap a NP-435 in for my E4OD with 3.05s and 31s and not be over revving to sustain 90mph for as long as I have fuel. my future plans include 37" Humvee takeoffs (haven't decided which tread pattern) and 3/4 ton axles. I've got a 4.10 and 3.54 3rd member and I need to know which ratio I should be looking for gears to match. I'm thinking that I'll striaght swap the 4spd and run 31s until I can swap to 37s and 3.54 gears at the same time.

If you go to 37" tire then you would want to stay with the 4.10 or even going to 4.88's. if you went to 3.54's with 37" tires you would have great top end but not power down low.

Here is a gear ratio to tire chart with rpm's.

http://www.jeep4x4center.com/jeep-tires ... -chart.htm

arse_sidewards · Post **#20** by **arse_sidewards** » Wed Dec 04, 2013 5:12 pm

300 6 JEEP wrote:
arse_sidewards wrote:
THE FRENCHTOWN FLYER wrote:I guess I need to qualify my answer a bit. The exhaust valve rotators tend to fail at sustained high speeds. If you are building an engine to run at sustained high speeds you should substitute INTAKE retainers on the exhaust valves, with, of course some springs that give the correct load (about 71 - 75 lbs) at the installed height.

I'm not building an engine for sustained high rpm operation. I'm trying to decide if I can swap a NP-435 in for my E4OD with 3.05s and 31s and not be over revving to sustain 90mph for as long as I have fuel. my future plans include 37" Humvee takeoffs (haven't decided which tread pattern) and 3/4 ton axles. I've got a 4.10 and 3.54 3rd member and I need to know which ratio I should be looking for gears to match. I'm thinking that I'll striaght swap the 4spd and run 31s until I can swap to 37s and 3.54 gears at the same time.

If you go to 37" tire then you would want to stay with the 4.10 or even going to 4.88's. if you went to 3.54's with 37" tires you would have great top end but not power down low.

Here is a gear ratio to tire chart with rpm's.

http://www.jeep4x4center.com/jeep-tires ... -chart.htm

Please do the math before telling me I'll need deeper gears. I have an E4OD, 31s and 3.05s now. I'm looking to have a NP-435, 37s and 3.54s in the future.

"NEEDS 4.10s bro!" Of course a jeep owner would say something like that. Are you going to tell me to adjust the choke on my EFI as well?

300 6 JEEP · Post **#21** by **300 6 JEEP** » Thu Dec 05, 2013 8:39 am

Please do the math before telling me I'll need deeper gears. I have an E4OD, 31s and 3.05s now. I'm looking to have a NP-435, 37s and 3.54s in the future.

"NEEDS 4.10s bro!" Of course a jeep owner would say something like that. Are you going to tell me to adjust the choke on my EFI as well?[/quote]

WOW! Sorry for trying to to give you some additional Information! I thought the poeple on this this site had a little bit more manners I was mistaken. I won't provide anymore information, and for your information my JEEP is just a shell and in it beats a ford Driveline.

blmhawkeye · Post **#22** by **blmhawkeye** » Thu Dec 05, 2013 9:03 am

3500 rpm
4.10 gears
1-1
37" tires
~91 mph

Looks like he did do the math...

Also if he hadnt suggested lots of others would have. I would have

arse_sidewards · Post **#23** by **arse_sidewards** » Thu Dec 05, 2013 2:39 pm

300 6 JEEP wrote:WOW! Sorry for trying to to give you some additional Information! I thought the poeple on this this site had a little bit more manners I was mistaken. I won't provide anymore information, and for your information my JEEP is just a shell and in it beats a ford Driveline.

As a Jeep owner (or any 4x4 owner/auto enthusiast), everything you say is wrong until proven right as far as I'm concerned. Where I'm from this "shoot first, ask questions later" skepticism has served me well. I know that came off as unnecessary, sorry if you're offended but it's rare that I'm given good advice.

blmhawkeye wrote:3500 rpm
4.10 gears
1-1
37" tires
~91 mph

Looks like he did do the math...

Also if he hadnt suggested lots of others would have. I would have

Maybe I didn't make myself clear. The NP-435 has a deep 1st and 1:1 4th. I intend to use big tires and tall gears (compared to other 3/4 ton stuff) to make 4th into something a little bit lower than my current 4th gear.

Here is a comparison of tire size /gear ratio. Tires don't heave nearly as much effect as gears.

3.55s and 37s is shorter than 2.73 gears and 29s (235/75/R15) and taller than 3.05s and 31s (what I have now). Considering that I usually cruise the highway in 3rd this should be a good combo.

67StockBlue · Post **#24** by **67StockBlue** » Thu Dec 05, 2013 2:41 pm

Alright, was able to pick up a T18 at the pull a part over the weekend. Per guhfluh advice, I think I will just keep the 300.

Also picked up the later EFI exhaust to add.

Another question. How will the MPG be effected if I gear the rear up to a 2.50. Is that going to be overkill? I can get them off eBay for the same price as a 2.75 ring and pinion. Has anyone done it? I understand the 300 will do well with a 2.75 gear ratio. I worry that I may actually lose gas mileage if it is too high. Again, not planning to pull anything with the truck, just a daily driver that I want to last a long time and can move furniture for friends when the move.

Respectfully,
Linwood

Post **#25** by **80broncoman** » Thu Dec 05, 2013 6:08 pm

67StockBlue wrote:Alright, was able to pick up a T18 at the pull a part over the weekend. Per guhfluh advice, I think I will just keep the 300.

Also picked up the later EFI exhaust to add.

Another question. How will the MPG be effected if I gear the rear up to a 2.50. Is that going to be overkill? I can get them off eBay for the same price as a 2.75 ring and pinion. Has anyone done it? I understand the 300 will do well with a 2.75 gear ratio. I worry that I may actually lose gas mileage if it is too high. Again, not planning to pull anything with the truck, just a daily driver that I want to last a long time and can move furniture for friends when the move.

Respectfully,
Linwood

Just so you know Ford built some F150s in the early 80s with 2.47 gear ratios rear axles.
The one truck i know about for sure was a 2WD 300 3 speed manual trans, 2.47 and 235 tires.
I'n not sure if they ever combined it with a OD trans.

blmhawkeye · Post **#26** by **blmhawkeye** » Thu Dec 05, 2013 7:18 pm

You might see a small increase for ur freeway driving and possibly a small loss in town for stop and go. I got 3.00s in the back of my truck and get bout .5-1mpg better than my buddy with 2.75s for in town

arse_sidewards · Post **#27** by **arse_sidewards** » Thu Dec 05, 2013 10:32 pm

the ultimate mpg combo would be something like:

-Kansas (statistically the most flat state)
-92 F150 (with lighening front valence) or 70s F100 (aerodynamically comparable to a 92, but thinner)
-stock springs after 40yr of firewood
-2wd
-8.8 rear
-non-overdrive transmission
-4x4 rear bumper (replacing stock parachute)
-rear gears chosen to work with tires (probably 31s to keep diff RPMs low)
-no fan
-manual steering
-chopped up stopsigns made into aerodynamic underbody tray
-etc, etc, typical eco mods

something like this should blow modern trucks out of the water for MPG all other things equal. One could go further but this is the easy stuff.

1986F150six · Post **#28** by **1986F150six** » Fri Dec 06, 2013 7:07 am

67StockBlue wrote:Alright, was able to pick up a T18 at the pull a part over the weekend. Per guhfluh advice, I think I will just keep the 300.

Also picked up the later EFI exhaust to add.

Another question. How will the MPG be effected if I gear the rear up to a 2.50. Is that going to be overkill? I can get them off eBay for the same price as a 2.75 ring and pinion. Has anyone done it? I understand the 300 will do well with a 2.75 gear ratio. I worry that I may actually lose gas mileage if it is too high. Again, not planning to pull anything with the truck, just a daily driver that I want to last a long time and can move furniture for friends when the move.

Respectfully,
Linwood

I owned a factory original [now belongs to my son] 1984 F150 with 4.9L, 215/75 X 15 tires, 4 speed manual OD and 2.47 rear gears. Pre gasohol, it would return a real 26 mpg on the highway @ 60-65 mph. At the first hint of an approaching incline, it would require a downshift to 3rd. Even @ 65 mph in 3rd, you could not hear the engine. It was not fun to drive slowly... it idled @ ~8 mph and would go to almost 40 mph in 1st.

The rear gears were changed to 3.55s and the highway mileage is now 20-21 mpg, but the fun factor is better!

Post **#29** by **Lazy JW** » Sat Dec 28, 2013 4:51 pm

arse_sidewards wrote:
THE FRENCHTOWN FLYER wrote:
arse_sidewards wrote: I find this kind of hard to believe. I always thought the six didn't like anything more than diesel revs.

Why would it be any less robust than a V8 with an equivalent stroke, say a 400M or a big block Chevy? It may have a hawrable volumetric efficiency at 5K because of the suckie manifolding but it will stay together at that steady sustained speed.

I guess that makes perfect sense, I just never thought of the 300 compared to other engines designed around the same time.

Ford put the 300 in trucks as large as the F-600 with gearing to allow 3500-4000 rpm at highway speeds.

Post **#30** by **Lazy JW** » Sat Dec 28, 2013 4:55 pm

67StockBlue wrote:Alright, was able to pick up a T18 at the pull a part over the weekend. Per guhfluh advice, I think I will just keep the 300.

Also picked up the later EFI exhaust to add.

Another question. How will the MPG be effected if I gear the rear up to a 2.50. Is that going to be overkill? I can get them off eBay for the same price as a 2.75 ring and pinion. Has anyone done it? I understand the 300 will do well with a 2.75 gear ratio. I worry that I may actually lose gas mileage if it is too high. Again, not planning to pull anything with the truck, just a daily driver that I want to last a long time and can move furniture for friends when the move.

Respectfully,
Linwood

My F-150 has the 2.75/T-18 combo and it is a genuine pig to drive around town in stop-and-go traffic. Granny gear is too low and second gear is too tall. Out on the road it is great.
Good luck with the 2.50's

Post **#31** by **Lazy JW** » Sat Dec 28, 2013 5:03 pm

arse_sidewards wrote:
... or for as long as it takes to burn 40 gallons of gas?

That should be about 20+ gallons per hour at 90+mph.... :lol:

Post **#32** by **Lazy JW** » Sat Dec 28, 2013 5:12 pm

blmhawkeye wrote:3500 rpm
4.10 gears
1-1
37" tires
~91 mph

Looks like he did do the math...

A stock 300 will be badly out of breath at that speed.

I have no idea how fast my 81 F-150 will go with the 2.75/T-18 combo but I seriously doubt that it has the torque to pull it to 100 mph.

Wind drag increases with the square of velocity, thus to go from 50 mph to 100 mph it takes four times the power. My TorqueMotor won't show above 10 inches of vacuum at 50 mph on level ground; I'm certain that it won't pull in enough air at double that speed to produce four times the power.

4.10's will definitely help a 300 in that situation.
Joe

arse_sidewards · Post **#33** by **arse_sidewards** » Sat Dec 28, 2013 10:27 pm

I'm pretty confident the 6 can keep a full size truck near triple digit speeds. I can keep the speedo pegged in 3rd. I run out of flat ground too fast to keep it pegged in 4th. If I ever go to Kansas I'll give it a try and report back. I know it'd possibly create an awkward gear ratio gap right where first gear should be but 3.08, 31s and the tall OD in the E4OD is way too tall for highway use IMO.

Post **#34** by **woodbutcher** » Sun Dec 29, 2013 6:10 pm

Hi 1986f150six.I think that gasohol was around long before 1984.
Good luck.Have fun.Be safe.
Leo

Oregoon · Post **#35** by **Oregoon** » Wed Jan 01, 2014 7:39 pm

I'm somewhat of a hypermiler, mainly because it amuses me on my 18-mile commute and also because I drive a semi for a living, so my driving style lends itself well to maximizing mileage. I regularly wring 41 mpg out of my '95 Corolla, and have managed 23 mpg in my old '94 F150 (EFI 4.9 in front of it a M5ODr2, with 272 rear-end, stock tires, and a lumber-rack). In order to get such numbers, I worked nights, and never dealt with as much as a red-light or a solitary tailgater. I coasted all hills, idled away from stop-signs, and never went over 55. On day-shift, in traffic using the same sorts of techniques, I made about 19 mpg.

My two cents: Avoid that Mazda 5-speed at all costs. Sure, it's okay for cruising around on the highway, it's lightweight, and it's got an overdrive. But it uses ATF, tends to leak, and once that starts, it's not long before you're hunting down another transmission. New they run $2500. And if you find one used, they're often the reason the truck is in the wrecking yard.

I maintain my vehicles meticulousy, and my trans bit the big one at 140K, which is apparently a good long run for an M5OD. It leaked when I got it with 40K on it, and it was the first thing I repaired. Once it died, rather than deal with a ZF5 swap, I sold the truck and moved on to the wild world of slickdom.

I am confident I can squeeze 20+ out of my 300, though I'll be rolling right-lane to make it happen.

motzingg · Post **#36** by **motzingg** » Thu Jan 02, 2014 12:13 pm

ah the m5 debate rages on! of course!

the one i pulled last weekend looks good, not a drop leaked and bright red fluid (doubt it was ever changed) with 121k on a truck used for heavy hauling... and i'm going to fully abuse the crap out of it, so i'll keep you posted. Even in the yard, the only time i could find them was in wrecked trucks, only one out of about 5 that i saw had the leaking plug. Most were clean and slightly greasy from leaking pushrod cover gaskets. one was in a thoroughly destroyed work truck. looked like it had been t-boned. I wish i had taken pictures.

Obviously, from an anecdotal standpoint, there are going to be failures of any mechanical component along a probability distribution of lifespan. You're a lot more likely to hear the 3% of 'early' failures before 150k miles (that is still a pretty decent run for a transmission) than the 97% that fall in the median, because the guys whose trans are still running don't have anything to talk about.

Maybe it is a weak trans, maybe they had bad QC or maybe the oil leakage problem is so severe on some, that oil gets out before the owner realizes and it gets run dry. Because ATF has much thinner film than gear oil, running dry or low for even a second could roach the journal bearings (also a weaker design point than the roller-heavy ZF), synchros, and roller bearings, whereas you can run a diff for 10,000 miles bone dry and not wreck it. I wouldn't even think of touching one that showed signs of leakage or running low on oil, maybe yours had already been cooked at 40k.

If you go on other ford truck forums people trash the reliability of the 300-6 because their dad had a fuel pump fail and dump gas into the crankcase in 1976 and kill the motor.... so its obviously a piece of crap! Ask me about Subaru 'EJ' motors sometime if you want to get controversial!! Or better yet, get 3 gearheads talking about 4.6 'mod' motors and you'll get 20 opinions (despite being ranked as a '10 best' engine for many years). Either way, ford wouldn't have put it behind a 200 ft-lb engine without a fair bit of testing. If their testing didn't simulate the aging and deterioration of the plug, or if they didn't realize it was being overtightened or had a mfg defect leading to a bad fit, some kind of molding flash, etc. that seems to me like a much more plausible situation.

but to the debate of fuel mileage, you'll be hard pressed to beat an M5

the thinner ATF will reduce frictional losses
the design is well suited for an efficient overdrive, with smaller lighter gears
its manual, duh, so there is no slip
it has narrow ratios so you can stay in the sweet spot of the power band longer
and its light weight, which, in the context of a flying brick weighing 3500 lbs might not matter much, but if you're really going for mileage, every little bit helps

Oregoon · Post **#37** by **Oregoon** » Thu Jan 02, 2014 8:06 pm

motzingg wrote:
ah the m5 debate rages on! of course!

but to the debate of fuel mileage, you'll be hard pressed to beat an M5

the thinner ATF will reduce frictional losses
the design is well suited for an efficient overdrive, with smaller lighter gears
its manual, duh, so there is no slip
it has narrow ratios so you can stay in the sweet spot of the power band longer
and its light weight, which, in the context of a flying brick weighing 3500 lbs might not matter much, but if you're really going for mileage, every little bit helps

I agree with your thinking there! I was stunned at how quiet and smooth my M5 was (until the end!), and I think the trans was a good idea for a 1/2 ton street truck. Were I to build anything beyond stock, or plan on some robust use (especially off-road), I'd go with a ZF--though to be fair, I tend to build everything like it's going to be dropped from a plane and I hate doing things twice. A fine way to build for longetivity. Not so good for economy!

FYI--mine started getting stuck in first, then reverse went out, then fifth. Then, terrible noises.

Post **#38** by **80broncoman** » Fri Jan 03, 2014 12:16 am

Oregoon wrote:......I agree with your thinking there! I was stunned at how quiet and smooth my M5 was (until the end!), and I think the trans was a good idea for a 1/2 ton street truck. Were I to build anything beyond stock, or plan on some robust use (especially off-road), I'd go with a ZF--though to be fair, I tend to build everything like it's going to be dropped from a plane and I hate doing things twice. A fine way to build for longetivity. Not so good for economy!

FYI--mine started getting stuck in first, then reverse went out, then fifth. Then, terrible noises.

I had to chuckle when i saw the words "terrible noises". One night my T-5 in my 85 Capri 5.0 started ticking like a bad lifter when I stuck it in 3rd as I was on the gas the ticking kept getting louder till,..... it made it to about 3800 RPM before the big LOUD noises happened all at once. Sheared the teeth off the cluster.

Soldmy66 · Post **#39** by **Soldmy66** » Fri Jan 03, 2014 10:51 am

WOW! Sorry for trying to to give you some additional Information! I thought the poeple on this this site had a little bit more manners I was mistaken. I won't provide anymore information, and for your information my JEEP is just a shell and in it beats a ford Driveline.[/quote]

I would have reacted the same way. You were trying t help, not afford an opportunity to be criticized.

I have something to contribute, but won't.

Oregoon · Post **#40** by **Oregoon** » Sun Jan 05, 2014 12:08 am

300 6 JEEP wrote:...my JEEP is just a shell and in it beats a ford Driveline.

Forget the arguing guys, I want to hear more about this Jeep! I had a '57 Willys Pickup years ago, and dreamt of putting a 300 in there. Such a torquey engine in such a nimble shell must make for an excellent 'wheeler.

As to the O.P.'s mileage question: Before you consider tires, gears, and trannys, it's best to consider how deeply you'll install your right foot. Sounds like that's been considered, and answered.

Keep us posted and best of luck.

Post **#41** by **80broncoman** » Sun Jan 05, 2014 1:17 am

Oregoon wrote:
300 6 JEEP wrote:...my JEEP is just a shell and in it beats a ford Driveline.

Forget the arguing guys, I want to hear more about this Jeep! I had a '57 Willys Pickup years ago, and dreamt of putting a 300 in there. Such a torquey engine in such a nimble shell must make for an excellent 'wheeler.

As to the O.P.'s mileage question: Before you consider tires, gears, and trannys, it's best to consider how deeply you'll install your right foot. Sounds like that's been considered, and answered.

Keep us posted and best of luck.

Keep in mind all Jeeps got a about a 3 inch wheelbase stretch going from 1971 to 1972 so that the AMC inline six could go in them.
A 300 will fit But I don't see it working in a older one.
1971 and older has inline 4s and Buick V6s

J.R. · Post **#42** by **J.R.** » Sun Jan 05, 2014 11:01 am

300 6 JEEP, thanks for your input and your link to that tire/gear/RPM chart http://www.jeep4x4center.com/jeep-tires ... -chart.htm Gears are gears; the math doesn't change with the badge on the hood.

I'll admit some prejudice for the Jeep/Ford combos; that's the subject of one of my own (all too long-term) projects. Dating myself a bit, but I can remember when flathead Ford V8s fit very nicely into old flathood Jeeps, and with a Warn overdrive, made them more versatile... or at least a lot faster!

J.R.
SoCal

Oregoon · Post **#43** by **Oregoon** » Sun Jan 05, 2014 12:46 pm

80broncoman wrote:
Keep in mind all Jeeps got a about a 3 inch wheelbase stretch going from 1971 to 1972 so that the AMC inline six could go in them.
A 300 will fit But I don't see it working in a older one.
1971 and older has inline 4s and Buick V6s

That's certainly a consideration. My best friend had a 292 Chevy in his '62 Willys Wagon (not sure how those compare to a 300's dimensions), and the radiator needed to live elsewhere. His 292 fit in the stock location, but a little frame-twisting up in The Tillamook State Forest, and the fan would make contact with the radiator fins. Several long, muddy hikes ensued.

As for an earlier CJ like you're referencing, I think there'd need to be a remote radiator, or some heavy firewall mods to make it work.

One day, perhaps... It's a cool idea, but what bench-racing idea isn't?

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