I have a 91 f150 with 302/e4od speed density combo. Would like to have a larger lotor but not sure if I can handle the 302 to 351 swap because of the electronic change over. Is it poss to build up a 302 to 327 or 331 and still use the stock speed density system. If so, what steps do i need to take or is there any articles anyone knows of I can research. Thanks for the help.

 

Stroke it.

The stock speed density ecm can handle the added cubic inches. If you elect to stroke it or go with a stock 351w, your only talking about 25-30 added ftlbs of tq over the 302 and minimal hp gain, so its nothing that the computer can't deal with.

Some people opt to reuse the 302 ecm when they do the 302 to 351w swap and it operates fine, so stroking it should be no different.

There is a stroker 347 kit available for the 302 as well. There used to be a problem with them burning oil due to the piston design, but the newer designs have taken care of that.

 

Thanks. Not sure which route to go yet as far as 331 or swap out completely for a 351. Would love to find a good donor veh and get 351HO with maf and get all the electronics.. Do you know if the computer modules are tranny specific? Would I need to find a donor that had a 351 and an e4od?

 

The computers are specific to the tranny.


Couple things to consider. By adding the 351w you roughly add 50-75 lbs. The 302 has a crank with smaller mains, which means it has less surface area and can spin a little quicker, not really a big plus in a truck application but a plus none the less, if you plan to race it some.

 

No racing with this truck. Got over that with my Mustang, too many responsibilities now. Need something that will have decent acceleration and able to pull a boat, travel trailer, and possibly horse trailer all while trying to maximize that best mpg I can get. I figured 331 would be the easiest route to go w/o having to swap too much stuff. I can get a stroker kit that has all the parts needed to change the 302 to a 331?

 

E4OD is computer controlled. So yes, the computers are tranny specific.

It is possible to use two computers. Your present computer to control the tranny and a mass air computer for the engine. I can't help with any details, but a web search should come up with a few things.

As for the computer being "fine" with the added displacement... From what I've heard, it will work, but your definitely better off converting to mass air.

 

The stock PCM should be fine with the 331 or the 351; however, I would suggest getting an adjustable FPR with the added cubes.

 

What is FPR and where can I get a good, affordable stroker kit for my truck? Also, can I change to a mild RV type cam and the GT40 heads while I'm changing everything out w/o having problems with my speed density? Thanks for any help, I have so many questions to ask before I get started.

 

i recently came upon this site www.airflowresearch.com they seem to have some of the best heads i've seen for the 5.0... emissions legal

 

FPR is fuel pressure regulator. Adjust the fuel psi to either lean or richen the air/fuel mixture, should a lean condition arise.

Don't get a specific rv cam, call a cam company and speak with the tech, they can give you a camshaft with the correct lobe sepertion to generate the amount of vacuum required to keep the speed density happy and provide great low end torque.

Add the heads, they aren't much better than what you have so it won't be anything that cannot be adjusted for.

www.enginekits.com

and

www.ebay.com usually has scat cranks at a good price

 

listen, the swap over to a 351 is easy. once the motor is droped in you reuse the 302 wiring harness and get a 351w ecu that uses your same tranny. its that simple. no modifing necessary. you want to tow and such this would be your best bet. you can spend so much money trying to make that 302 into a truck motor but it still will be unmatchable to the 351w's potential in every way. i found a junkyard complete 351w for $800 bucks total when finished was 975. now i have a better motor for future upgrades, got plenty of torque to pull and play in. i even get better mpg because the motor doesnt work as hard to push our Brick ON wheels. what your thinking about stroking is a spendy endevor because of your tranny and such. if you have any ??'s regarding this swap let me know

late

 

Something to consider:

the 5.0 was rated at 180-205 hp and 270-275 tq
the 5.8 was rated at 200-210 hp and 300-325 tq

Going the stroker 5.0 route you would better the stock hp figured of the 5.8. There is a chance you would equal the tq output of the stock 5.8. By going the stroker route, you would end up with a fresh bottom end and remaned heads run $200+/-. With the 5.8 you would have an engine with a fair amount of miles on it that eventually needs to be rebuilt. No denying that if your after a great amount of hp and tq or even more cubes the 5.8 is the way to go. In my area it would be cheaper to do the stroker 302 vs buying a used 5.8.

 

but motor head , he also would need either a tweecer or mass air conversion that cost 1500 to run that motor. you can build a 393 stroker for the same price as stroking a 302 to a 347. the 302 is a high reving motor meant for a car. in a 4x4 you want low end grunt for pulling and 4x4in. when you start revving a motor to high with a 4x4 stuff start breaking. unless your a mug bogger the 351w is the only way to go its the best bang for your buck.

 

I see the positives in both cases. It just depends on what you want to do. The 351 is an easy swap. You also have too look at how much more torque the 351 makes at idle to 1500 rpm. It will be more than the 331. That is what counts when you are towing, or just comming off the line from a stop light. Either way, you will have to jump into a project, whether it is boring out your cylinders and line honing your block for the 331, or making a wider y pipe or finding a suitable intake for the 351, and freshening it up, as well as finding a good motor. You have to choose what you want. In my opinion though, either way you go, stay fuel injected.

 

I can't see a reason for him to have to run mass air or a tweecer, even if he did you can get a selectable chip for 380+/- and keep the speed density or go with a homemade mass air $500+/-. The 302 is a high revving engine that was also put in trucks. For ever die hard 5.8 lover your gonna have another saying the 302 is a work horse. Not certain why you would be revving the motor extremely high either, the aftermaket cam profiles are identical for the 5.0 and 5.8 and recommened for the same rpm range. Given it will operate a hair higher with the 5.0 but in theory you can take the 351w and 302 operating range and divide that in half if he's gonna run the 331, if he runs a 347 I wouldn't be suprised if the rpm difference was minimal. Locally a complete 351w efi goes for $1000-1500 complete with ecm and who knows how many miles, so as you can see going with a 302 stroker is a whole lot more economical, from where I sit. I just put it out there for consideration, no different than whether you like pepsi or coke, its a matter of opinion.