Hi Guys

My Father and myself would like to upgrade our 1989 f150 from the original 302 efi to a 351w efi. Our hope is to find an 351 that will plug
into the existing harness and cause as few installation problems as possible. My question is does the computer have to be changed so
it doesn't think it's running the old 302? Our truck did come with the 351
option but we didn't expect to be towing a trailer and the 302 is a bit tired, is this swap going to be a real problem? We really need a stronger pulling truck and can't afford a new one. Any info you have would really help us out.

Thanks
Mike

 

The 302 computer will run the 351 fine, its a fairly easy swap , Conanski will be along shorty , he has done this swap ....Lew

 

You need a complete 5.8 EFI motor and then it's a simple bolt-in with a 28oz flywheel/flexplate for whatever transmission you have. Do not change anything else besides the plug wiring order. The 5.8 should work pretty good after the computer has a chance to adapt, but if it doesn't come around finding a 5.8 computer for it shouldn't be too hard, there were lots of 5.8 trucks in the late '80's and early '90s that would make good donor candidates.

 

Thank you very much guys!, i'll pass your messages on to Dad. We just
can't justify paying $35.000 (if lucky) for a new truck, and our truck is much loved by our family (being the only truck\car Dad ever bought new) it would be a real shame to replace it.

Mike

 

How much weight do you pull and is the truck all stock with gearing and tires or not? Also what trans is in it?

 

I suggest getting a 351 computer to go along with the engine. The fuel mapping for the 302 will not work very well with the 351. I ran a 351 computer on my 302 to test the computer and it ran like crap. As these other guys have said, just use the original 302 wiring harness - it will work with the 351 computer too.

 

Hi Guys
We where planning on pulling a car trailer and maybe a large camper (long term idea)
the truck is stock gearing I think 3.00:1 with aod trans, we wheren't planning on changing
the gears but maybe adding a better set of leaf springs. Does anyone know who would sell
a stock rebuilt 351w? All I can find are preformance engines.

Mike

 

You are pretty close to the limits of what an F-150 can handle with a car trailer (assuming there is a car on it). The trailer weighs 1500 lbs or so and then add the weight of a car. You could be seeing a 6000 lb trailer and that's about all you want to be pulling with an F-150.

Your AOD trans will bolt up to the 351w but you are going to have to put in a few trans upgrades if you are using it behind a 351 and planning on towing. An external cooler and a shift kit are really going to help the trans last behind that motor.

And gears... there is no such thing as stock gearing, and the 3.00 ratio was only offered with the Ford 9" axle which your truck doesn't have. If you don't have at least 3.55 gears you are going to be very unhappy with the towing performance no matter what you do to the trans and engine.

Jasper sells rebuilt 351w's and I've heard good things about them. Also check into adding a cam and exhaust to the build, as the 351w is strangled by the factory exhaust and cam. It will really wake the motor up (at least that's what Paul says and he is the resident SBF expert )

 

Yeah your going to want lower gears like 410 , I agree with shift kit & cooler for the AOD , you could get the gear sets & shaft out of a 4R70W , & put it in the AOD this will lower your 1 & 2 gear ratio & make it stronger ...Lew