300 is not a performer

[tj300]

Any one expecting a big horse power gain with a few performance bolt ons is in for a big disappointment, especially with an automatic transmission behind it. On my 300 I have the Offy DP intake, 500cfm 4bbl. carb, dual outlet header, true duals, and an MSD ignition upgrade. Originally, my engines output was 117hp, and I think about 223 ft.lbs. of torque. I would estimate, with the performance upgrades, my power output to be only nearly equal to that of a stock EFI 300. I did notice a pretty decent power gain on the freeway. But in town the gain is hardly noticable. There's nothing wrong with the engine. It runs very good and only has 76k original. Gas mileage remained the same, terrible as ever. These engines are notorious for bad mileage. And the carbed engines are noisy. I like the engine for it's reliability and ease of maintainence. I've read some posts where people spoke of plans to build their 300s to an output of 300hp. I hope you have a big bank account. You can get more performance out of a V8 with less money. A hardshift kit and a stall convertor just above stock may help some, but then there's the issue of a 3:14 gear ratio. Translates to more big money. Anyone have a 351w of equal condition they'd like to trade?

[crash-harris]

Auto trannies make slow dogs of 300's, another reason why I'm proud to be a sticky

[Ronbo]

I guess it depends on what you are working with. In my case it's an 83 that had the electronic feedback carb complete with cracked exhaust manifold. Just changing out the distributor and carb to a late 70s version made a huge difference. New high flow cat and dynomax muffler added to it. The whopper was the DP/390 and headers. I'm running 3.55s on 32s with the "indestructible" SROD managing the gears. It does what it was meant to do and quickly! Then again, I never intended to have a street burner when I was done.

Ron

[American Thunder]

Any one expecting a big horse power gain with a few performance bolt ons is in for a big disappointment, especially with an automatic transmission behind it. On my 300 I have the Offy DP intake, 500cfm 4bbl. carb, dual outlet header, true duals, and an MSD ignition upgrade. Originally, my engines output was 117hp, and I think about 223 ft.lbs. of torque. I would estimate, with the performance upgrades, my power output to be only nearly equal to that of a stock EFI 300. I did notice a pretty decent power gain on the freeway. But in town the gain is hardly noticable. There's nothing wrong with the engine. It runs very good and only has 76k original. Gas mileage remained the same, terrible as ever. These engines are notorious for bad mileage. And the carbed engines are noisy. I like the engine for it's reliability and ease of maintainence. I've read some posts where people spoke of plans to build their 300s to an output of 300hp. I hope you have a big bank account. You can get more performance out of a V8 with less money. A hardshift kit and a stall convertor just above stock may help some, but then there's the issue of a 3:14 gear ratio. Translates to more big money. Anyone have a 351w of equal condition they'd like to trade?

I took the 302/C6 out of my bronco, rebuilt a stock '95 300, a 5-speed trans, and and bolted it all in. With a '72 intake and carb, points distributor, stock 3.55 gears, my Bronco averages 22 mpg, and has for the last 10 months or so. With the previous 302, msd ignition and all that stuff, it was averaging about 10 mpg. The 300 pulls a trailer up hills better than the 302, and when cruising empty, the bronco will maintain its speed on hills in overdrive. I also spent quite a while adjusting the fuel and ignition curves, by taking apart the carb and distributor several times.
If your 300 runs weak, I'd suggest tuning it.
Also, I wouldnt use the 500 2bbl, I would use a 390 4bbl for better fuel mileage.

As for V8s making power, yeah, they do, my 302 makes over 500 hp, and will rev to 8500 rpm(with a very substantial monetary investment) but even in the Mustang that only weighs 2450 lbs, it gets 13 mpg highway and 1 or 2 mpg town driving. And even the built 302 can't touch the 300 in torque where it counts in a truck.

If you need a LOT more power than the 300 is making, and you're positive it's tuned perfectly, then I'd suggest investing in a 460, not a 351. Mileage won't be much different between the sbf and bbf, unless you're in the throttle a lot, and a 460 will rip a 351 to pieces.

[willowbilly3]

I agre, if you are going V8 why put a thirsty 351 when you can have a 460 with about the same fuel consumption.
If your 300 is getting crappy milage then their is either something wrong with the set up or something wrong with your driving habits. I have found that 300s don't like to be crowded. In stock form I have noticed mileage with drop off a lot by just pushing from 55 to 65.

I'll trade you a good 351 for your 300, if you leave all the goodies on it.

[Harte3]

I've gotten 18.5 at 60-62...17.3 pushing and holding 70-72 on a 800+ mile trip to the coast and back...18.4 on a trip down to Riggins, ID and back with two big climbs to make...Whitebird and Lewiston Hill with a total of about 15 miles of 7% grade. Around town on cold starts and short trips about 14. No problem plugging around on 30 mph streets at 900-1000 rpm and getting a smooth and quick acceleration when going aggressive.

If you are running a 500 cfm 4v it's an Edelbrock? Should be no problem at all when it's dialed in. Could it be the secondary air flap might stand some "tightening" to delay the opening a bit say to about 2000-2500 rpm? Otherwise you may be getting a bit of bog when mashing the gas at low engine speed.

[tj300]

Any one expecting a big horse power gain with a few performance bolt ons is in for a big disappointment, especially with an automatic transmission behind it. On my 300 I have the Offy DP intake, 500cfm 4bbl. carb, dual outlet header, true duals, and an MSD ignition upgrade. Originally, my engines output was 117hp, and I think about 223 ft.lbs. of torque. I would estimate, with the performance upgrades, my power output to be only nearly equal to that of a stock EFI 300. I did notice a pretty decent power gain on the freeway. But in town the gain is hardly noticable. There's nothing wrong with the engine. It runs very good and only has 76k original. Gas mileage remained the same, terrible as ever. These engines are notorious for bad mileage. And the carbed engines are noisy. I like the engine for it's reliability and ease of maintainence. I've read some posts where people spoke of plans to build their 300s to an output of 300hp. I hope you have a big bank account. You can get more performance out of a V8 with less money. A hardshift kit and a stall convertor just above stock may help some, but then there's the issue of a 3:14 gear ratio. Translates to more big money. Anyone have a 351w of equal condition they'd like to trade?

I took the 302/C6 out of my bronco, rebuilt a stock '95 300, a 5-speed trans, and and bolted it all in. With a '72 intake and carb, points distributor, stock 3.55 gears, my Bronco averages 22 mpg, and has for the last 10 months or so. With the previous 302, msd ignition and all that stuff, it was averaging about 10 mpg. The 300 pulls a trailer up hills better than the 302, and when cruising empty, the bronco will maintain its speed on hills in overdrive. I also spent quite a while adjusting the fuel and ignition curves, by taking apart the carb and distributor several times.
If your 300 runs weak, I'd suggest tuning it.
Also, I wouldnt use the 500 2bbl, I would use a 390 4bbl for better fuel mileage.

As for V8s making power, yeah, they do, my 302 makes over 500 hp, and will rev to 8500 rpm(with a very substantial monetary investment) but even in the Mustang that only weighs 2450 lbs, it gets 13 mpg highway and 1 or 2 mpg town driving. And even the built 302 can't touch the 300 in torque where it counts in a truck.

1.)If you need a LOT more power than the 300 is making, and you're positive it's tuned perfectly,

2.) then I'd suggest investing in a 460, not a 351.

Mileage won't be much different between the sbf and bbf, unless you're in the throttle a lot, and a 460 will rip a 351 to pieces.

1.) Yeah, it seems to be tuned ok.

2.)I did give it some thought but they seem to be hard to find. Those who have 460s don't want to give them up. Especially to swap for a 300. Aside from that my truck is a 1980 short bed F100. Curb weight around 4700lbs. I think the 351w would work out fairly well. The 460 would have been perfect for my 7000lb. F250.

[Lazy JW]

..... I also spent quite a while adjusting the fuel and ignition curves, by taking apart the carb and distributor several times.
If your 300 runs weak, I'd suggest tuning it.....

Yup, methinks the original poster has a bit of tuning to do.

From your description it sounds like my 81 F-150 could stand a bit of tuning in the fuel/ignition curves (I haven't even touched them). It has only averaged 19+ mpg over the last 46,000 miles. I thought that was pretty good but your Bronco has me beat. Keep up the good work
Joe

[tj300]

1.)I agre, if you are going V8 why put a thirsty 351 when you can have a 460 with about the same fuel consumption.

2.)If your 300 is getting crappy milage then their is either something wrong with the set up or something wrong with your driving habits.

I have found that 300s don't like to be crowded. In stock form I have noticed mileage with drop off a lot by just pushing from 55 to 65.

3.) I'll trade you a good 351 for your 300, if you leave all the goodies on it.

1.)I'm certainly up for it if I can come across someone who'd be willing to swap it out for a 300,( of equal condition).

2.)Everything is in real good working order. The only times I ever put my foot to the throttle was to test the new goodies.

3.)PM me with what you have, 351c, 351w, condition, etc.

[tj300]

1.)I've gotten 18.5 at 60-62...17.3 pushing and holding 70-72 on a 800+ mile trip to the coast and back...18.4 on a trip down to Riggins, ID and back with two big climbs to make...Whitebird and Lewiston Hill with a total of about 15 miles of 7% grade. Around town on cold starts and short trips about 14. No problem plugging around on 30 mph streets at 900-1000 rpm and getting a smooth and quick acceleration when going aggressive.

If you are running a 500 cfm 4v it's an Edelbrock? Should be no problem at all when it's dialed in. Could it be the secondary air flap might stand some "tightening" to delay the opening a bit say to about 2000-2500 rpm?

2.) Otherwise you may be getting a bit of bog when mashing the gas at low engine speed.

1.)Actually, that's about what I'm getting. Seems like I'm looking at mileage differently.

2.)I thought I did notice a bog.

[tj300]

..... I also spent quite a while adjusting the fuel and ignition curves, by taking apart the carb and distributor several times.
If your 300 runs weak, I'd suggest tuning it.....

Yup, methinks the original poster has a bit of tuning to do.

From your description it sounds like my 81 F-150 could stand a bit of tuning in the fuel/ignition curves (I haven't even touched them). It has only averaged 19+ mpg over the last 46,000 miles. I thought that was pretty good but your Bronco has me beat. Keep up the good work
Joe

Yeah, maybe you guys are right.
I'm just discouraged with the engine. I like Harte3's 300 build. It's a more reasonable goal for this motor. But yet, the cost and work of getting just 235hp.
I just think the automatic transmission and 3.14 gear ratio is pulling this engine down. It really drops off between shifts. If I decide to keep it I'm going to put a shift kit in it for now. Stall convertor and 3.73s ,at least , when I can afford it later on.

[Harte3]

Mine pulls a bit soft...I wouldn't call it a bog...from low speed...1000 rpm in high gear when mashing the gas but picks right up and pulls hard once it gets to 2000-2500 rpm...just the nature of the beast.

4700 seems a bit heavy. Mine weighs in at about 4100 with me in it...a little bit more now since I found a used Leer canopy in good+ condition this winter and installed it.

[tj300]

My upgrades have been somewhat incremental. Here's what I noticed at each stage. First of all, the emissions were toast. They're gone. Could have a small power gain there, but not really noticable.

Even with all my upgrades, in town power gains were only modest. Again, the auto tranny and 3.14 ratio could have a bit to do with that.

My gains were more noticable on the freeway. They were only decent gains.

Stock, my truck struggled after 55mph to reach 60-65 mph.

Of all my mods I noticed the biggest gain when I upgraded the igniton with MSD, 6a box, Super conductor wires, Blaster coil, and a good dizzy cap with brass contacts. No struggle to reach 65mph. Got there pretty quick.

Next was Offy DP intake, 500cfm carb, dual outlet hedder, true 2' duals all the way back exiting at rear bumper through high flow turbo type mufflers. Absolutely no struggle to reach 80mph.


Driving through town under 45mph it's a complete dog. I'm nowhere near satisfied with intown power gains.

Here's my guesstimate on my current horse power:
Stock: 117hp-30% for auto tranny, weight= around 87rwhp.
All the modifications combined, I'm guessing about 30 extra hp, giving me around equal hp to an EFI 300. 147hp-30%=102rwhp. A lot of money for just a gain of only 15rwhp.

[tj300]

1.)Mine pulls a bit soft...I wouldn't call it a bog...from low speed...1000 rpm in high gear when mashing the gas but picks right up and pulls hard once it gets to 2000-2500 rpm...just the nature of the beast.

2.)4700 seems a bit heavy.

Mine weighs in at about 4100 with me in it...a little bit more now since I found a used Leer canopy in good+ condition this winter and installed it.

1.)I guess that could describe mine to a point, only yours is pulling better than mine, once I get on the freeway it moves pretty good.

2.)A neighbor lady slid into my truck over the winter causing some minor damage. Her insurance adjuster checked the vin, and the paper work sent to me indicated 4700lbs. But I'm inclined to believe they could possibly have that wrong because that seems heavy to me also.

[cougeuph]

I was questioning the 4700 lbs too. My 80 doesn't weigh that much and it's a supercab with 8' box.

BTW from my experiance a 300 will never beat a 460 for raw power but...

In high school a frind with a 70's ford 460 w/ auto couldn't move a trailer but my 300 w/ stick and granny could. (at idle slightly riding clutch). He kept spinning his tires.

[Stealth Bummer]

Some V8s do get better mileage than 300s. But then, Clydesdales eat more than Shetland ponies.

[Ranger_gone_straight]

300 happy spot is around 2100 -2200 rpm. Adding more breathing capability will not change that, it will just give bit more power at higher rpm if you push it.

If I wanted a high rpm engine, I'd get a short stroke overhead cam engine. They rev happily/easily and make their max power high in rpm range.

As to mileage from my experience and apparently others, 18 to 20 mpg is very good for 300. You want to bitch about mileage, I was getting 14mpg in my little 4wd Ranger with 2.8L bent six and it was dangerously slow in traffic. That was really insult to injury. When a Ranger with small engine can only beat a F250 by couple miles to the gallon and a dog to drive as well...

As to 460, there was one in my 3/4 ton 4wd when I bought it though truck had apparently come from factory with a diesel. Admittedly it was about worn out but got a whopping 4mpg. Needless to say it didnt get used very much and it was down to either selling it or swapping in something useful for my needs. I swapped in a 300 and very happy. Mileage around 12 to 13mpg and believe me a healthy 300 vs a worn out 460 is a no brainer. I've driven good 460s, still take a good 300 unless I had to tow big load at high speeds, but thats just me. I like low rpm "tractor" engines. I dont care about going 90 mph, just want some get up and go upto 60mph and hill holding power. Guess I'm getting old.... I like very quiet engine also.... Yep getting old.

[80broncoman]

That DP intake is for a stock like build. look at it this way the runner divider takes up space in the plenum and runners. this make the runners half the size till the secondays open up. they will open faster on ta 390 CFM carb. They were made for 390 Cfm carbs and good MPG. If you want performance in the 2500 and up rpm you need a 25000 and up intake.
Have you done anything to increase the compression and or head flow?
If not do not expect gains over what you have.

[mutt]

rading this m thinking perhaps Ill get a better dist. cap.....what brand has brass contacts? This is an 80 distributor. I might play recurve, too.....

[StrangeRanger]

A few random questions:

Is this truck a 2WD or a 4WD? Regular or extended cab? 4700# is way too heavy for a 2WD regular cab short box. My 96 2WD RC/SB with an E4OD is only about 4100# and it has 16 years worth of smog and safety upgrades vs. your 80.

Are you sure about a 3.14 axle ratio? I've never come across that one before. What axle is it? What tires are you running? At what pressure are they set? It has a real effect on both performance and economy.

What do your plugs look like? Black? Grey? Aluminum flecked? Tan?

Have you checked for vacuum leaks?
Is the vacuum advance in your dizzy working properly?
What is your total advance and at what RPM do you get there?

Do your secondaries remain closed until you intend for them to open? Do they open fully when you open the throttle?

[tj300]

A few random questions:

1.)Is this truck a 2WD or a 4WD?

2.) Regular or extended cab?

3.)4700# is way too heavy for a 2WD regular cab short box.

My 96 2WD RC/SB with an E4OD is only about 4100# and it has 16 years worth of smog and safety upgrades vs. your 80.

4.)Are you sure about a 3.14 axle ratio?

I've never come across that one before.

5.) What axle is it?

6.) What tires are you running?

7.) At what pressure are they set?

It has a real effect on both performance and economy.

8.)What do your plugs look like? Black? Grey? Aluminum flecked? Tan?

9.)Have you checked for vacuum leaks?

10.)Is the vacuum advance in your dizzy working properly?

11.)What is your total advance and at what RPM do you get there?

12.)Do your secondaries remain closed until you intend for them to open? Do they open fully when you open the throttle?

1.)2WD

2.)Regular cab

3.)I'm going to agree that you're correct. I'm possibly mistaking a #1. as a #7. recalling the insurance paperwork that was sent to me. But, I'm not for sure. I agree that 4700# a bit much

4.)There's a metal tag on the differential stamped 3.14. I remember looking at it a few times hoping it was stamped 3.74, and not 3.14. No such luck. I hope I'm proven wrong.

5.) I don't know. I just know it's a 9inch rear.

6.)P235/75R15. I changed out the truck tires and had the oem size for that truck installed for the added perfomance.

7.)35psi

8.)Tan

9.)Yes. Everything checks out good. No leaks.

10.)I don't know.

11.)I really don't know that one either.

12.)I would almost say yes, except I remembered a slight hesitation a couple of times when I suddenly put my foot into it. On the freeway it responds well.
I do have a C-6 3spd.auto transmission.
Hope this is helpful. Thanks.

[tj300]

1.)That DP intake is for a stock like build.

look at it this way the runner divider takes up space in the plenum and runners. this make the runners half the size till the secondays open up. they will open faster on ta 390 CFM carb. They were made for 390 Cfm carbs and good MPG. If you want performance in the 2500 and up rpm you need a 25000 and up intake.

2.) Have you done anything to increase the compression and or head flow?

If not do not expect gains over what you have.

1.)Except for hedders, exhaust, and MSD ignition, it's stock.

2.)Not yet.I'm waiting for finances to get better. Headwork and a cam is going to be my next engine project. But a shift kit and a stall convertor may be my next project.

[StrangeRanger]

Is there still a vehicle ID plate on your door jamb?
If so what is the axle code from it?

[tj300]

Is there still a vehicle ID plate on your door jamb?

If so what is the axle code from it?

I went out and checked. It's missing.

I did find this:
http://www.realsteel.co.uk/section12.pdf

Scroll down to Rear Axle "Diff Carrier Gasket"
Ford 9" 3.14. Would that be the ratio? Actually, when looking at it, 3.14 may be the purchase price. It's foreign. I can't tell. May be # instead of $.

[StrangeRanger]

Nope. That's the price in British Pounds Sterling.

9" ratios are typically 3.00, 3.25, 3.50 etc. not 3.14. I think you're reading some other line besides ratio off the tag

[tj300]

Nope. That's the price in British Pounds Sterling.

9" ratios are typically 3.00, 3.25, 3.50 etc. not 3.14. I think you're reading some other line besides ratio off the tag

Any other way to tell? The ride in my truck feels a little low for a 3.00 ratio.

[StrangeRanger]

If you have an open diff:
Jack up (1) rear wheel leave the other grounded
Put the tranny in neutral
Make a chalk mark on the driveshaft where you can easily see it.
Turn the rear wheel that is in the air through (2) complete rotations
Count the rotations of the driveshaft.
The number of rotations is the ratio e.g. 3-1/4 rotations of the shaft is a 3.25:1 ratio.

If you try the above and the wheel in the air will not turn you have a limited slip diff, in which case:
Jack up the rear end with both wheels off the ground.
Put the tranny in neutral
Make a chalk mark on the driveshaft where you can easily see it.
Turn the rear wheels through (1) complete rotation.
Count the rotations of the driveshaft.
The number of rotations is the ratio e.g. 3-1/4 rotations of the shaft is a 3.25:1 ratio.

[tj300]

If you have an open diff:
Jack up (1) rear wheel leave the other grounded
Put the tranny in neutral
Make a chalk mark on the driveshaft where you can easily see it.
Turn the rear wheel that is in the air through (2) complete rotations
Count the rotations of the driveshaft.
The number of rotations is the ratio e.g. 3-1/4 rotations of the shaft is a 3.25:1 ratio.

If you try the above and the wheel in the air will not turn you have a limited slip diff, in which case:
Jack up the rear end with both wheels off the ground.
Put the tranny in neutral
Make a chalk mark on the driveshaft where you can easily see it.
Turn the rear wheels through (1) complete rotation.
Count the rotations of the driveshaft.
The number of rotations is the ratio e.g. 3-1/4 rotations of the shaft is a 3.25:1 ratio.

Okay. Thanks.

I just can't figure out what the 3.14 stamped on the tag was about. I'm puzzled. You don't think 3.14 meant 3 1/4 rotations do you? I don't know, just a thought.

[American Thunder]

If I recall, my 4x4 Bronco weighs about 4200 lbs, so a 2wd shortbed F150 should be a little lighter, I'd think. Maybe 3900-4000?

[82F100]

When I had my 82' I put it on the scales at the track and it weighed 3,675lbs minus ac stuff but that was with duel tanks and such.Mine would run anywhere from 60-75 with out missin abeat. Even drove it to Tucson about 90 miles and raced it with 3.55's would run about 3,000 rpm at 65 mph with a short tire.Also before i changed gears I had 2.73s' in the 9".

[StrangeRanger]

I once had a 72 GMC with a 307 and a 3 on the tree regular cab 8' bed and power nothing. It weighed in at 3650 IIRC. 4700 is practically F250 territory in a 1980.

I'm almost expecting a 2.75 rear end in a 1980 with an I6. It would have been marketed as a fuel economy package. (And a complete stone at anything less than or much above 55 MPH)

[Harte3]

Sounds like two things are working against you...the auto tranny and a tall geared rear end.

[American Thunder]

Nope. That's the price in British Pounds Sterling.

9" ratios are typically 3.00, 3.25, 3.50 etc. not 3.14. I think you're reading some other line besides ratio off the tag

I have an original set of 1960 Thunderbird 9" 3.10 gears in my Mustang. I wonder if they're still available? hmm

[American Thunder]

I once had a 72 GMC with a 307 and a 3 on the tree regular cab 8' bed and power nothing. It weighed in at 3650 IIRC. 4700 is practically F250 territory in a 1980.

The 1972 F250 I had with a 360 FE, cast iron trans and case, and 40" mudders weighed 4500-4600, but it didnt have a bed on it. What's an 8' bed weigh, 400?

[82F100]

Another thought .. How big are your duals? I would also agree with having the distributor recurved, BTW where is the timing set?

[tj300]

Sounds like two things are working against you...the auto tranny and a tall geared rear end.

Oh yeah, that's part of my discouragement with this engine.

The 300 does not do well with tall gears and an auto tranny. I was even wondering if a shift kit and a little higher stall convertor would help. The running condition of my engine is excellent. It's just a poor performer. Even with the performance mods on my engine I'm still not that much above stock. Stock, the 300 is just naturally a sluggish engine. I do like the 300 build you have.

[StrangeRanger]

It is not a sluggish engine.
You are either pulling a set of "economy" gears or there is something seriously wrong with your tuneup.
Please check the gear ratio so we can eliminate or confirm that as the source of the problem.

[tj300]

1.)Another thought .. How big are your duals?

2.) I would also agree with having the distributor recurved,

3.) BTW where is the timing set?

1.)2"

2.) Even with the mods I'm still pretty much stock. Do you believe it would help or be necessary?

3.) Actually, the timing has never been touched. What would you suggest?

Still, there's the issue of high gearing and an auto transmission. If I decide to keep it I'm thinking towards a shift kit and and a little higher stall convertor. Just wondering if that would help.

[tj300]

It is not a sluggish engine.
You are either pulling a set of "economy" gears or there is something seriously wrong with your tuneup.
Please check the gear ratio so we can eliminate or confirm that as the source of the problem.

Fair enough. As soon as the rain clears out of here I'll check it out.

[82F100]

As far as timing I've run as much as 15deg when I was racing quite a bit. FYI I had an 82' with a 300 & C-6 Mac headers and 3.55's, Truck ran a best of 17.68 at about 82mph and that was with about 120k on the odometer.
You might also consider the Chevy rocker arm swap to help a lil bit if you still have the stock cam in it( kinda like a cheap RV Cam).

[80broncoman]

Are you running the ignition timeing at the stock specs? If so remember stock specs are for a stock engine and vehicle. run as much timing as you can for the octane of fuel you are going to run whith any pinging.

[tj300]

As far as timing I've run as much as 15deg when I was racing quite a bit.

FYI I had an 82' with a 300 & C-6 Mac headers and 3.55's, Truck ran a best of 17.68 at about 82mph and that was with about 120k on the odometer.
You might also consider the Chevy rocker arm swap to help a lil bit if you still have the stock cam in it( kinda like a cheap RV Cam).

Here's my question, Wouldn't I lose some bottom end power?
I did that with my 302 at 12deg and noticed a loss of bottom end power. But I did gain the improvement more in the mid to top end. But if it's determined that my complaint is actually due to highway gearing and the auto tranny instead of tuning issues,(which I hope is the case),I still have to work around that somehow. In any case, I'll wait and do as strangeranger suggested and go from there.

[tj300]

1.)Are you running the ignition timeing at the stock specs? If so remember stock specs are for a stock engine and vehicle.

2.) run as much timing as you can for the octane of fuel you are going to run whith any pinging.[/quote}

1.) I am running the timing at stock specks. I would have to say that my engine is basically stock. Here's what I have, Offy DP intake, Edelbrocks Performer 500cfm 4bbl., dual outlet Hedman hedders, true dual 2" exhuast exiting at the rear bumper, high flow turbo style mufflers, no cats, MSD 6a box, MSD Super Conductor wires, MSD Blaster coil. As far as headwork, cam, and any internals the engine is bone stock.

2.)I've used high test gas in the truck ever since I owned it. It does not like 87. It chatters and runs hot on 87.

[StrangeRanger]

...I've used high test gas in the truck ever since I owned it. It does not like 87. It chatters and runs hot on 87.

In that case, you may have too much advance dialed in. It should run perfectly with no detonation and no spark knock whatsoever on 87 octane. You're not running enough compression to warrant higher octane. If the timing is right then you probably have some hot spots from carbon buildup.

[Harte3]

Even though the internals are stock, you still have modified the engine which tends to throw the arbitrary stock setting numbers out the window.

Try setting the dizzy with it unplugged and the vac line plugged and a vac gauge connected to a full manifold vac source. Turn the dizzy until the highest steady vacuum is indicated and back off 1-2 hg. Then adjust the idle mix using the same proceedure...obtain the highest steady reading...and then adjust the idle speed. Hook the dizzy vac back up, drive and try. If you get ping under load, back the dizzy off in small increments until the rattle stops when under heavy load or only slightly pings under very heavy load. Readjust the carb and you should be good to go.

[mutt]

to second Harte here- the timing number is a ballpark figure that you tailor to your gas/altitude/how hard you are on the throttle.
Im old enough to remember degrees stamped into some distributor hold downs, with a line adjoining in te block. this was the "octane selector"- an easy way to reference small changes in timing to suit conditions.....

[82F100]

Something I just thought of... do you have full throttle,ie. when pedal is to the floor are the butterflys wide open? I agree with the others on the timing to try to get the motor dialed in on regular 87 octane fuel. Are you still running a cat or cats? on your exhaust system?
You might try some Slick50 carb cleaner in a tank or two aswell. I had good luck with it getting rid of some carbon buildup in my truck.

[john-dickjr]

Any one expecting a big horse power gain with a few performance bolt ons is in for a big disappointment, especially with an automatic transmission behind it. On my 300 I have the Offy DP intake, 500cfm 4bbl. carb, dual outlet header, true duals, and an MSD ignition upgrade. Originally, my engines output was 117hp, and I think about 223 ft.lbs. of torque. I would estimate, with the performance upgrades, my power output to be only nearly equal to that of a stock EFI 300. I did notice a pretty decent power gain on the freeway. But in town the gain is hardly noticable. There's nothing wrong with the engine. It runs very good and only has 76k original. Gas mileage remained the same, terrible as ever. These engines are notorious for bad mileage. And the carbed engines are noisy. I like the engine for it's reliability and ease of maintainence. I've read some posts where people spoke of plans to build their 300s to an output of 300hp. I hope you have a big bank account. You can get more performance out of a V8 with less money. A hardshift kit and a stall convertor just above stock may help some, but then there's the issue of a 3:14 gear ratio. Translates to more big money. Anyone have a 351w of equal condition they'd like to trade?

guess i will tell my grandpa that there is no way that he can make power with a 300, o he only ran 10.70's with a 300 ci straight 6 thats in the 1/4 mile

[82F100]

Any one expecting a big horse power gain with a few performance bolt ons is in for a big disappointment, especially with an automatic transmission behind it. On my 300 I have the Offy DP intake, 500cfm 4bbl. carb, dual outlet header, true duals, and an MSD ignition upgrade. Originally, my engines output was 117hp, and I think about 223 ft.lbs. of torque. I would estimate, with the performance upgrades, my power output to be only nearly equal to that of a stock EFI 300. I did notice a pretty decent power gain on the freeway. But in town the gain is hardly noticable. There's nothing wrong with the engine. It runs very good and only has 76k original. Gas mileage remained the same, terrible as ever. These engines are notorious for bad mileage. And the carbed engines are noisy. I like the engine for it's reliability and ease of maintainence. I've read some posts where people spoke of plans to build their 300s to an output of 300hp. I hope you have a big bank account. You can get more performance out of a V8 with less money. A hardshift kit and a stall convertor just above stock may help some, but then there's the issue of a 3:14 gear ratio. Translates to more big money. Anyone have a 351w of equal condition they'd like to trade?

guess i will tell my grandpa that there is no way that he can make power with a 300, o he only ran 10.70's with a 300 ci straight 6 thats in the 1/4 mile

Any pics of his car??

[American Thunder]

tj, ignition timing and air/fuel ratio can make your motor scream like heck or run like a complete pig. (or a chevy)
Generally, the state of tune is more important than adding speed parts. So many people spend all kinds of time bolting on stuff, and then skip the most important part.. TUNING!

My bone stock 300 will leave rubber in 1st gear if I punch the throttle. It doesnt feel sluggish at all. It's jumpy and ready to rock and roll. I'm running higher initial timing than stock. I think 12-13 degrees, if I recall. I don't use my Bronco for towing anymore, (that's what the wife's EB Bronc is for) so I can run my timing right on the ragged edge and get away with it.