Best Engine for a 1978 Ford F-150 Build?
FTE member needs your help in choosing a new powerplant for his classic F-150 build!
Oftentimes, the specifics of truck builds are set in stone way ahead of time. Many of us have a very specific idea of what our dream ride should look like. And that includes the type of powerplant you throw under the hood. Maybe it’s an old school carbureted mill or a fuel-injected, overhead cam engine. Then again, sometimes these decisions don’t come so easy. Which is the case with FTE member lakequ and his 1978 Ford F-150 project.
But that’s where the Ford Truck Enthusiasts forums come in handy, you see. If you’re looking for some solid advice on your next project, where better to find it than from a place packed with thousands of like-minded enthusiasts? So that’s exactly what the OP did by starting this thread.
“I am almost to the point in my build that it is time for me to decide on what I want to do with the engine. That being said, it had a 351M in it and that is what I want to put back in. But the original engine isn’t in very good shape. And I do want it to be fuel injected. So should I try to get a crate motor or should I rebuild the one I have and do the EFI upgrade?? What are your opinions on it? What would you do if it was your truck?”
Right away, 85e150six4mtod delivers some thoughts surrounding both proposed engine options.
“The usual fix for the 351M is to make a 400 out of it. Put pistons in with 9:1 or better compression, a decent cam, 4 barrel intake, and carb to match the cam/compression, etc. If you want to go EFI, there are several to choose from and it appears they get better all the time.”
But as Blue and White points out, neither the 351M nor the 400 are common options in the aftermarket. So maybe it’s better to stick with what you’ve got in this case.
“For the basic engine, there are not a lot of 351M crate engines that I know of. The rebuilds sold by AP stores seem pretty spotty on quality. Rebuilding the one you have is a good option. You just need to find a decent shop to help.
The 351M and 400 share the same block, manifold, and accessories. The difference is the crankshaft and pistons. The 400 gains displacement and there are quite a few upgrade parts available for it, which is why it is a popular upgrade for the 351M. See TM Meyer.
For the EFI, I run an older FAST system on a hot rod which has been good. As mentioned, there are lots of other good systems out there now.”
Several folks, including PA74F250, suggest making the swap to a more common (and better supported) 460, however.
“A 400 definitely does run better than a 351M if it has the usual mods. 351s are turds, and I would never rebuild one, let alone waste money on fuel injection for it. I had a 400 in my ’79 but switched to a 460. If I didn’t have all the stuff to do it, I may not have. But I didn’t know if my 400 was worth messing with. With that being said, I do not miss my 400 at all. My 460 is so much better. I’m going to say my mpg is slightly better with my 460 too.”
And yet, the OP is more interested in sticking with what he has for simplicity’s sake. In which case, boingk has some solid advice for the build.
“A 400 would be great, but stay away from 4V ports if you can. They deliver great high rpm usability, but it’s not what these engines are about unless you spend big coin on them.
A standard 2V is plenty for the street, and the aftermarket made a raised 3V that is the best of both worlds. Either of those is fine and will give good usability and power with something resembling economy if you set it up right.
I’d aim for about 10:1 compression with a decent closed-chamber aftermarket head, a twin-plane intake (RPM Airgap is a good option) and moderate camshaft (something in the .500″ lift and 220 duration at .050″ ballpark) like an Elgin E-907-P.
Headers are a must with those upgrades. And a twin 2.5″ exhaust system will be more than sufficient for the power it makes while still staying reasonably quiet when you want it to be. It’ll let out a good note if you put your foot down, too.
EFI is great, but honestly a well set up carb is still fine today. Both my truck and my Valiant run used Holleys that I have put a basic kit through and cleaned up before installing. They run fine and start easy hot or cold. I’d save the money and avoid the hassle of EFI by staying carbureted. If you really do want EFI, it is a large investment and the installation process relies on many sensors. The modern kits are very good and self-tune generally. But as I said, a well set up carb is still a good thing.”
All of which is great advice. But we want to know, which engine route do you think the OP should go in his 1978 Ford F-150? Head over here and chime in with your thoughts!