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TeamNeptune

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This is what I have done so far. What if anything is not correct for my usage. What should be considered for improvements in performance.
I have a 1978 ford Ranger 4x4 with 35" tires. T18 trannie. I primarily use it to pull my boat. It has a reconditioned block that is stock as far as I know.
Here is the list of modifications I have done.
Edelbrock 500 carb. mechanical sec. re-jetted secondary's to match the primaries.
Clifford 4bbl. intake
Comp. cam 268
early 60's 240 head tapped for 7/16 rocker studs with stock rockers, (intake 1.875) (exhaust 1.60) performance valves. No porting.
efi exhaust manifolds.
I am currently installing 4.11 differential gears to offset the over sized tires. It will take a while for me to recover from this expense.
Tires I know are costing me but I just like the way they look and it will se some 4 wheeling during hunting season.
Cam ??.. Larry says it is all wrong and should replace with his. With the 4.11's I will be hauling on the highway at around 2700 rpm and I wanted the engine to have a slight lope . I like the sound.
The only problem that I was having and keep in mind this was before the gear swap is staying up to speed on the highway.
long hills would cause my speed to drop off from 70mph to 55mph frequently.
 

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Fordman75

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The gears are the right step. If you current combo is tuned right you will have no issues running at highway speeds.

And Larry is the last person I would take build advice from.
 

pmuller9

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Your combination is good. The Comp 268 cam should make plenty of torque from 2000 rpm and up.
Was the cam installed as recommended with the intake lobe center near 106 degrees ATDC?

What is the ignition timing at idle and full mechanical advance at 3000 rpm with the vacuum advance disconnected?
 

TeamNeptune

Active member
I installed the camshaft as per directions. Seems like I remember it only being marked to go one way. As far as timing I would have to recheck it to be sure. I should probably check it at 3000. The timing at Idle was close to 10 deg. advanced with the vacuum unplugged. I advanced it some from there until I was hearing some valve rattle then backed it off just a touch. Last time I hauled the boat out it was with the 3.50 gearing I was at WOT at least 1/3 of the time and got just over 11mpg.
I will check the total advance at 3000. The vacuum seems to work best off of manifold.
 

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jason832

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I have a similar setup as you. 4barrel street demon, Clifford intake, headers, 268 cam, no head work, 4 inch lift, 3.55 gears, np435, 35inch bfg km2s. I have my timing tuned quite well and a wideband AFR meter. I have the street demon tuned very crisp. I rarely count milage but on a long haul if I hold 60mph I can nearly crack 20mpg not towing. I did one trip with a tandem axle car hauler and burned around 14mpg at 60mph. I cruise just touching the gas at less than 5% on level ground...

How heavy is that boat? Looks like a pile of weight and air drag. 11mpg prob isn't that bad....

The vacuum advance should be on ported vacuum. There's a spot somewhere on the carb for it. Check the vacuum advance arm moves a tad when you blip the throttle. Once timing is right start thinking wideband AFR meter if you want to push milage. The 3.55 gears will do fine unless you tow regularly. The cam should also be good, not perfect for towing but great for an empty truck.
 

TeamNeptune

Active member
Jason how about a picture.
I think my boat is right around 2000lbs. I don't know where you live but out on the highway here between Charlottesville and Va Beach everybody and there grandmother will be flying by you if your doing 60mph. I can see 65mph while pulling the boat but empty, at least on the interstate I would be at 75mph. I live 30 miles east of the Blueridge mountains and its not exactly flat ground. When the truck is not pulling and empty and on flat ground yes I don't need to be into the throttle much either. They sent me the wrong dif.carrier for my dana 44 or the gears would have been done this weekend. I expect to be cruising the backroads here in the 1700-1800 rpm range at 45- 50mph with the new gears.
What type of AFR gauge do you have ? I am thinking that is a good idea.
After reading post for about 2hrs. last night I am a little concerned my Edelbrock 500 may be lean in the secondary. Plugs have been looking right, with just a small amount of tan but I would like to be able to see whats going on with the fuel mixture. Like I was saying I have the Eddy 500 jetted the same on both sides.
Thanks for your help, JD
 

jason832

Well-known member
I don't think the weight is too much of an issue until he hits a good hill, which he can downshift to 3rd if he needs to, that cam will pull well at 4000rpm. Pulling that truck and boat on level ground at highway speed is like 2 parachutes.... I've pulled a lot more than 2000 without much problems.

My AFR ratio gauge is the popular aem one. It works very well, you can see the change one jet size has easily.
https://www.summitracing.com/parts/avm-30-4110

If the truck doesn't spend much time on the highway empty, I would support 4.10s. But on the other side of the argument, how much gas could you have bought with that money.... Even going down to 33s on your next tire set would make a difference.
 

TeamNeptune

Active member
Jason at the miles I drive it will be 5 years before needing new tires.
It looks like your carb is facing north to south. I am thinking about going 1 step up on my secondary jets and just keep my foot out of it until the rpm’s are up. I don’t think dropping to 3rd is a good option. JD
 

THE FRENCHTOWN FLYER

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TeamNeptune":oekcryby said:
...After reading post for about 2hrs. last night I am a little concerned my Edelbrock 500 may be lean in the secondary. Plugs have been looking right, with just a small amount of tan but I would like to be able to see whats going on with the fuel mixture. Like I was saying I have the Eddy 500 jetted the same on both sides.
Thanks for your help, JD

While I do not have a lot of experience with Edelbrock carbs specifically I can tell you that many four barrel carburetors are jetted on the lean side on the primaries. Carb makers want you to get as much fuel economy as possible. To compensate for the overly lean primaries the secondaries are often calibrated to be rich-of-optimum, so that the overall mixture going into the engine at WOT is near correct.

Soooo, if you leaned the secondaries to match the primaries you now have an overall too-lean mixture when pulling heavy loads, as you suspected.
 

TeamNeptune

Active member
THE FRENCHTOWN FLYER":1gcfrwu6 said:
TeamNeptune":1gcfrwu6 said:
...After reading post for about 2hrs. last night I am a little concerned my Edelbrock 500 may be lean in the secondary. Plugs have been looking right, with just a small amount of tan but I would like to be able to see whats going on with the fuel mixture. Like I was saying I have the Eddy 500 jetted the same on both sides.
Thanks for your help, JD

While I do not have a lot of experience with Edelbrock carbs specifically I can tell you that many four barrel carburetors are jetted on the lean side on the primaries. Carb makers want you to get as much fuel economy as possible. To compensate for the overly lean primaries the secondaries are often calibrated to be rich-of-optimum, so that the overall mixture going into the engine at WOT is near correct.

Soooo, if you leaned the secondaries to match the primaries you now have an overall too-lean mixture when pulling heavy loads, as you suspected.
Yes that would seem to be the case. I hope nothing has been hurt in the engine.
 

THE FRENCHTOWN FLYER

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I doubt that any damage occurred. It might take sustained running with an overly lean condition to do permanent damage as the carb is probably not calibrated that far from optimum.

When I worked on the Mustang 5.0 GT program we had some secondary metering plates made up that corrected the fat secondaries and when installed in conjunction with a jet change to the primaries it perked up that ol' girl a bit more. Not available to the motoring public of course.
 

TeamNeptune

Active member
I am still searching but last I read was with the 240 head and large cam you should be running at least 89 octane ?? I have the COMP cam 268 would this be true in my case.
JD
 

pmuller9

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TeamNeptune":11hb69bi said:
I am still searching but last I read was with the 240 head and large cam you should be running at least 89 octane ?? I have the COMP cam 268 would this be true in my case.
JD
The Comp 268 cam has the same advertised duration as the stock cam so if you use the 240 head and raise the compression to 8.8 or more you cannot install the 268 to the cam card spec which is intake lobe center at 106 degrees ATDC without detonation.
The stock cams intake lobe center sits at 114 degrees which gives you a much lower Dynamic compression ratio that the Comp 268.

If you use one of the other brand cams like Crower or Schneider, they have advertised durations of 280 to 284 for near the same Comps .050" duration of 218 degrees.
Then you can use any grade pump gas you want with a 9:1 compression ratio.
 

TeamNeptune

Active member
pmuller9":8er9zwby said:
TeamNeptune":8er9zwby said:
I am still searching but last I read was with the 240 head and large cam you should be running at least 89 octane ?? I have the COMP cam 268 would this be true in my case.
JD
The Comp 268 cam has the same advertised duration as the stock cam so if you use the 240 head and raise the compression to 8.8 or more you cannot install the 268 to the cam card spec which is intake lobe center at 106 degrees ATDC without detonation.
The stock cams intake lobe center sits at 114 degrees which gives you a much lower Dynamic compression ratio that the Comp 268.

If you use one of the other brand cams like Crower or Schneider, they have advertised durations of 280 to 284 for near the same Comps .050" duration of 218 degrees.
Then you can use any grade pump gas you want with a 9:1 compression ratio.
Ok I read that quote last night from a previous post. I installed the 268 @ 4* advance which was recommended by comp cams.
So you are saying I will have detonation with any grade of gas or I should go up to 89 octane ?
 

TeamNeptune

Active member
Right now my truck has the front wheels axles and gears out waiting on the carrier to come in. I don't really want to start it and rev it up to 3000 to check where the timing is with it being on jack stands. This weekend weather permitting I will have it back together.
I will check and see where it is at 3000 rpm and also 2700 rpm which is where it will likely be seeing most of its WOT.
Where should the mechanical advance from the distributer be at 2700 rpm ?
I would say 34 btdc
 

pmuller9

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34 to 36 degrees total advance is a good place to be for ignition timing.
You said that you moved the timing till there was detonation and then backed off a little.
If you find that you are at 34 degrees at 2700 to 3000 rpm then all is good.
if the timing is less then you can go to 89 octane to see if you can advance the timing closer to 34.
 

Lazy JW

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TeamNeptune":e5mycsb1 said:
... out on the highway here between Charlottesville and Va Beach everybody and there grandmother will be flying by you if your doing 60mph. I can see 65mph while pulling the boat but empty, at least on the interstate I would be at 75mph...

Whee! :D

I don't remember ever having my ol' White Ox going THAT fast! :mrgreen: :shock: :lol:
 

Fordman75

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Lazy JW":210tnbce said:
TeamNeptune":210tnbce said:
... out on the highway here between Charlottesville and Va Beach everybody and there grandmother will be flying by you if your doing 60mph. I can see 65mph while pulling the boat but empty, at least on the interstate I would be at 75mph...

Whee! :D

I don't remember ever having my ol' White Ox going THAT fast! :mrgreen: :shock: :lol:

I use to run faster then that with my old 86 F150 stock 300/4spd 2wd 3.08 gears, 31" rear tires pulling a loaded 20 foot car trailer.
 

bubba22349

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TeamNeptune":381pcq2y said:
Right now my truck has the front wheels axles and gears out waiting on the carrier to come in. I don't really want to start it and rev it up to 3000 to check where the timing is with it being on jack stands. This weekend weather permitting I will have it back together.
I will check and see where it is at 3000 rpm and also 2700 rpm which is where it will likely be seeing most of its WOT.
Where should the mechanical advance from the distributer be at 2700 rpm ?
I would say 34 btdc

So did you degree the cam when you installed it? :nod:
 
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