PDA

View Full Version : 302 to 351 swap???


C.W.
11-24-2008, 11:35 AM
I have a 91 f-150 with a 302 efi that i want to swap for my 351w, the 351 is currently carbed am i going to run in to any snags bolting a 351 efi intake on it and all my 302 sensors?
Any experiences that people have run across is helpful and appreciated.

bigorange440
11-24-2008, 12:00 PM
the 351 and 302 oil pans are different as the oil pump is deeper on a 351 the motor mounts will be ok but the ecm i know is different and i think the harness is a bit different too..i think u will need the complete new harness sensors and ecm

mus-Tard
11-24-2008, 12:48 PM
l was looking into that same swap. the 351 is wider and you will need a computer for the 351 because it has a map sensor it will inject the amount of fuel for a 302. l think intake manifold and plenum are basicly the only other things you need to watch out for.







but l may be wrong.

C.W.
11-24-2008, 01:01 PM
I have the oil pan covered, will the 302 sensors not work?
Is the ecm a plug and play or is it a completely different harness?

mus-Tard
11-24-2008, 01:11 PM
what year is the 351?

C.W.
11-24-2008, 01:17 PM
what year is the 351?
Not sure exactly?
Is there a date code on them? Im more familiar with gm stuff.

Deathtrap
11-24-2008, 09:14 PM
The 302 and 351 have different deck hieghts, so you cant swap intakes. ECU's are different, Not much difference in engine wiring harnesses I believe. The 351 will bolt directly in place of your 302. If the 351 has or had a V-belt setup you will need to change out your water pump as a serpintine belt setup has a different rotation. Your best bet is to find a truck with a efi 351 already in it and swap everything, you can probably find everything you need electrical wise and Pick'n pull in the westside.

C.W.
11-24-2008, 09:43 PM
I am getting a 351 intake.
How much difference is there in computers between trucks with aod transmissions and the e4od?
I have the e4od and was told i need to retain the computer and fuel injection to control it. Is that the case?

Deathtrap
11-25-2008, 10:24 PM
Well as far as I know and have seen, the 351 never came with the AOD, so yes you will need the e4od comp to run it, but I happen to have lying around somewhere here a 351 ECU out of a 90 F-250 with a 5spd that I would be willing to part with. It would work for ya if your running a 5spd or a AOD or another manual trans.
I was gonna use it for my 302-351 swap but have decided to drop in a 5.9 12V cummins instead[36]

C.W.
11-25-2008, 10:35 PM
I have the e40d in my truck right now, was hoping to keep it since it was rebuilt with a shift kit.
I do have an aod too though

Deathtrap
11-26-2008, 08:05 PM
Well Since you already have the e4od rebuilt, just find the biggest tranny cooler you can fit in your truck. Avoid using the AOD, they are power robbing and arent very durable/strong.

C.W.
11-26-2008, 08:22 PM
Thats the plan, just need the proper computer.

BajaDale
11-29-2008, 02:11 PM
The 302 and 351 have different deck hieghts, so you cant swap intakes. ECU's are different, Not much difference in engine wiring harnesses I believe. The 351 will bolt directly in place of your 302. If the 351 has or had a V-belt setup you will need to change out your water pump as a serpintine belt setup has a different rotation. Your best bet is to find a truck with a efi 351 already in it and swap everything, you can probably find everything you need electrical wise and Pick'n pull in the westside.

Don't forget to change the water pump AND TIMING COVER!! The 302 timing cover and water pump will work on the 351, but all your accesories have different barackets.:confused0006: It's really a worthless swap unless you're going to a performance 351. the older carbed 351w's aren't much better than the EFI 302's! Deathtrap is right, find a 351 EFI and swap everything in at once that way there is no second guessing if it'll work.