I have a 1970 Ford F250 Highboy (4X4) with a problematic 390 in it. I am tired of sinking more money in it and am tempted to either replace it with another FE or going with something bigger and more powerful.

Here is some information about what I have and what I want.
Have:

1. 4 spd Manual NP435
2. Divorced transfer case
3. 4.10 rearend

Want:

1. EFI 460 or PSD Engine
2. Keep a manual transmission (the NP435 would be great since I can keep the divorced transfer case)
3. Not worried about fuel economy if I go with EFI 460.

My big questions are:

1. How hard is it to swap in a 460 into a bumpside (67-72) pickup?
2. Would I need a new transmission or can the NP 435 handle a EFI 460 or a PSD engine?
3. Can I keep the divorced transfer case? If I can't, how hard is it to put a married transfer case onto a bumpside?
4. Do you see any red flags on why I shouldn't do this swap?

This pickup is very sentimentally important to me and money (within reason) is not a major concern. I want a strong, dependable truck. You can see photos of it in my galleries.

I looked through this forum to see if anyone has asked these questions before and found nothing. If you know of another post that covers this, please post a link to it.

I appreciate all information and suggestions.

Thanks,
Karl

 

While the 460 would be a worthy project, lots of things change, like mounts, bell, possibly clutch linkage, cooling, accessories, plus the extra 100lbs of road hugging weight on the front end.

You said possibly another FE. What is wrong with your "problematic" 390?

With a 428 crank, you have a 410. There is aftermarket EFI available. And look in the FE threads for several 390 builds. One in Hot Rod mag a while back got well over 400 hp without much trouble.

Even though I won't be doing the work, running for parts, going from scrappy to scrappy, doing and redoing things and spending the money, I always think an upgrade using the existing engine family is a better bet. Your money goes for primo heads and manifolds, better grade of headers, etc vs. motor mounts, accessory drives, relocated brake master cylinders, new bell housings, on and on.

Just my biased opinion. Good luck.