Looking to build a 302 for my 88 f250 flatbed. It currently has stock 302 n 5 speed, 18' beaver tail, i scrap and regularly am at about 20k (pulling 24' trailer with a car on each) i like that i get 15-17mpg empty, and 12 loaded. I dont like hillls loaded. Been thinking about putting together a 302 built just for towing/efficiency. Starting with a 99 explorer 5.0, 9.0-9.5-1 comp roller cam, long tube hedders. Mass air conversion, 460 rad and elect fan. My goal is 250hp and as close to 400lbs of torque as can get. Any suggestions on cam? Are my goals realistic? I hopin to squeeze a lil more mpg outta it and maintain speed on hills better

 

interesting idea, I have been out of this type of stuff for so long.


Seems like you are on the right track. I would also consider something like a mild turbo to push some more air and maybe at least go to throttle body fuel injection.


I am moving this to where I think more of the engine building folks hang out.

 

Sorry no, you will never see 400lb-ft from this displacement. You can get about 350lb-ft out of it but it'll be up around 3500rpm and you have to build the motor to make 350-400hp.

For what you are doing you need a diesel, but a step in the right direction would be a larger displacement gasoline engine. A 351w is a direct swap and it can be configured to reproduce something close to our goal.. 380-400lb-ft torque at relatively low rpms.

 

Id love a deisel honestly, and if this 302 wasn't doin remarkably well id def be more inclined to switch. I honestly dont want to switch to 351 my experience with them as been basically the same power just uses more gas (kinda like 318/360) i had one in my 87 bronco that i got from original owner in 99 with 34k... never seen better then 12mpg this truck at quadruple the weight gets about 12. I will be swapping axles. The guy who built this truck did a very nice job on frame and bed, but jusy put duallys on the rear its not even a full floater n im guessing the gear ratio is 3.55. I got the opportunity to pick up a sterling full floater rear outta a f350 with 4.10 gears the 1 ton spring pack with over load springs and 4 ten ply tires for $100, i got my eye on a d60 front with 4.10s for $300 as well. I think that alone would help tremendously. The thought of twin turbos has crossed my mind, i currently have 3 volvos in my yard with turbos n intercoolers i could rob for parts. How do i know for sure if i have the zf or mazda trans? Has anyone used the gt40p heads for a towing build? (Sorry for rambling i put 3-5k a week on my truck so i have lots of time to think lol

 

Back then those motors did make the same power, the way they were configured for smog compliance really crippled the bigger motor. That means you haven't experienced what the 5.8 is capable of and believe me there is no comparison. I had similarly equipped 5.0 and 5.8 motors in my '90, both motors were essentially stock but had better aftermarket cams and a full exhaust system with headers, so the factory restrictions had been removed. Same truck, same gearing and transmission.. the 5.8 was 3 seconds faster 0-60 and would climb hills without losing speed or downshifting where the 5.0 wouldn't. If you look at the factory dyno curves for these two motors they look similar but close inspection reveals that the 5.8 makes more torque at 1500rpm than the 5.0 makes peak, that isn't a small difference.

Great deal and yes gears will help tremendously.

If you have an F250 or larger and it has a granny low 1st it is a ZF. There were some light duty F250s in the late '80s that may have got the Mazda trans but I'm not sure on that. What is the GVWR on the drivers door pillar?

 

Since trucks been down, ive been reading reading reading. I think i have decided to build a 351w, with gt40p heads 9.5-1 comp. Roller cam probly go with 5.0 ho cam unless someone can suggest a better stump puller. Long tube headers and a 5.0 upper on 5.8 lower mass air, not looking to brake the bank (who is) ill be gathering peices. I scrap, its only a matter of time b4 i grab a 99 explorer with bad trans for $50

 

Conanski, its def a light duty f250, it dont even have a full floater rear, i just seen a pic of the zf trans and i pretty sure thats not what i have. So I'll be lookin at pickin up a zf as well. Its kinda scary honestly how "light duty" this flat bed really is. With a few swaps (engine, trans, both axles... lol) it'll be a bullet proof beast. So far it does what i need but i suspect the original owner/builder didnt use it daily at capacity

 

351W definitely the way to go and will run great with your suggested parts. I know your said your not looking to break the bank, but you should consider buying a 393 crank kit (Ford Engine Kit - Ford 393 Stroker Kit, 351 Windsor Reverse Dome) if your building a fresh motor. Torque will pull your trailer, more cubes is better!

 

Did I read correct that you are at 20k lbs?! With a 302?!!! It must be very flat where your at because my truck wouldn't do it! The problem with the 302 is the short stroke large bore configuration that it has, it dosent build low rpm torque well. For towing I would be looking into a bigger engine, if you build the 5.0 your gas mileage will go down the crapper anyway so why not make it easy on yourself. I would suggest you go for the steepest gears you can get first and think about an engine swap later. Nothing will help your towing performance like gearing for the $ spent.

 

For the Roadkill Rotsun the did a turbo 5.0 out of an 86? Mustang bone stock from the heads down just a carb intake and blow thru Holley and made 500ftlbs with a powerstroke turbo.

 

Has this gone anywhere? Since nothing is final on my build i would consider this for my 5.8. it's getting a rebuild would I have to buy the Stroker kit and a rebuild kit?

 

Didn't they change or grind the rings. I saw that episode.

 

Not on the 5.0. They figured 147,000 miles had opened the gap enough.
They filed them on a different engine though.