I have a '93 F150 with the 5.0 EFI. Not enough power for pulling trailer, or even going up a hill with a headwind!
I have the opportunity to put a recently rebuilt 351 ('89) that has been bored and stroked with a little over 300 HP in my truck. I intend on using my existing EFI, alternater, AC, etc. I understand I will have to find a different lower intake to fit the wider 351.
Am I going to regret this swap?! Even though it will physically fit, is it too much of a change and what wopuld be some of the obsticles I will run into? (I'm considereing a junk yard 351 computer. Or just change the plug wires at the distributor to accomodate the different 351 firing order?)

 

1. Front accessory drive brackets will be a problem. Go to a ford dealer(preferably one you may friendly with, or does not mind having someone ask annoying questions considering you will probably not buy anything from them) and pull up picture blow-ups and compare part numbers from the 302 drive brackets to the 351 brackets. more than likely, most parts will have the same number except one or two, and you will need those brackets.

2. If this 351 has a bigger cam than stock( and you need to know what the specs on the camshaft are, it may be totally inappropriate for EFI use), you will need to switch your existing speed density computer arrangement to a mass air flow setup, it will come with a computer. Look to the ford truck aftermarket, or ask who has done it here, I can't remember the details.....

3. Your exhaust Y-pipe will have to be modified(the 351w block is wider and taller than a 302) or replaced with a stock 351w truck unit. Headers would also be a really good idea here, along with a flowmaster catback.

4. Fuel system: If this engine is modifed, then it would be a good idea to switch to at least 24lb. per hour injectors, maybe even 36lb depending on cam size, and you will need to install a bigger fuel pump, around a 190 liter per hour rating. You need to tell the company you buy the aftermarket mass air flow sensor from what size injectors you are running, so they can give you the proper calibrated sample tube.

5. Intake: yes, you will have to get a 351 lower intake. It might be a good idea to get a bigger throttle body at some point....

6. You need to get an 351 EFI distributor for the same year, and you need to know if your new engine has a roller cam, to get the proper dist. gear for it.

7. Is this truck equipped with an automatic tranny? And if it is, is it an AOD? If it is, and if you are putting something modified in front of it, you really need to replace the torque converter, because the stock converters are really evil about ballooning even behind stock 3.8 v6's or 302's. Replace it with an aftermarket converter, most have stronger cases than stock, and most allow you to ditch the lock-up.

It is not that difficult to replace this setup, but EFI does create some more headaches than a carb arrangement intially, but is worth it when you don't have to fight with it in the morning.......
There is probably something I am forgetting......

 

Yes, flywheel/flexplate, and harmonic balancer, you must use the 351 setup...

 

[updated:LAST EDITED ON 26-Oct-02 AT 11:18 PM (EST)]One footnote to the first step on the first reply . If you go to a ford motorsport dealer or look in a catalog you can get a bracket kit for a 302-351 swap . I can't find my Motorsport book, but I thinks its about $50.00. That might save you a little research time for something else.

 

Tes, it has an automatic tranny.
Thanks for your insightfull input. Sounds like a lot of extra work, which always translates into lots of cash.
Once the project is completed I know I'll have a "tire burner" under the hood ... But at what cost?

 

What do you think of "my other option" :
Put a stroker kit in it to bring it up to a 331, RV cam, spacer between upper and lower intake manifolds, &/or smaller lighter pully wheels on the alternator, AC compressor, power steering, etc.???
I would probably have to at least get a custom burned chip to go with these changes. Right?

 

with the cost of a stroker kit you would probably be cheaper going with the 351 with more torque too.