My Husband and I just purchased this 1975 High Boy F250 4x4.
She had a 390 in her, but the it wiped the cam and was removed and sent to shop never to be seen again (by the previous owners).
We are looking at replacing it with a 351m or a 400. We are totally undecided. Our dream motor would be a 460. But in our area, they are hard to find.
Any feedback, opinions?

 

Welcomed to FTE

No such thing as a 400m, it's just plain 'ol 400.

1968/76 F100/250 4WD ~ Only available V8: 360 2V / On sale day, 360's magically become 390's!

Swapping in a 351M/400 will require all sorts of mods, as neither were available until 1977. And if your truck has a C6 (A/T), it won't work with a 351M/400.

You'd be better off finding a 360 or 390. The bore is the same (4.05"); the stroke is different: 360 = 3.50" - 390 = 3.78."

 

oops sorry, slip of the digits

 

NumberDummy, it has a 4 speed with granny. We know the bell housing has to be swapped out as it is different in a 390. What other mods are we talking about?

 

1965/76 352/360/390 (FE engines) use the same bell housing (except 1965 F100/250 352 4WD; 1965/66 352 F350; 1966 F250 352 4WD).

351M bell housing same as 400, but there are two different types beginning in 1979.

Clutches are different sizes, 1977/78 351M/400 clutch linkage is mostly different than 360/390. Beginning in 1979, it's all different.

351M/400 engine supports and rubber motor mounts are different than 360/390.

I'm not a fan of 351M/400's as they were very prone to cracking cylinder heads.

 

So the bell housing I have from the 390 will work if I put in the 351m/400? The 351m we have is from a 78 a/t truck, the 400 is out of a 77.

 

You cannot use an FE bell housing with any other engine size.

 

We would love to put the 390 back in, but it is gone, and finding one around here is hard. The 351m has had nothing done to it as far as we can tell, the 400 has been redone. We know there will be some mods we will have to do. Is it impossible to put one of these in the 75?

 

You can install a 351M/400, or a 460 if you wish, all it takes are the correct parts and money, lots of it.

I find it hard to believe that in the great state of VA .. you cannot find a 360 or 390 engine.

360: 1968/76 F100/350 / 390: 1965/67 Thunderbird & misc 1965/71 Ford/Merc Passenger Cars, 1968/76 F100/350.

1958/64 FE engines will not work on 1965 and later as the bolt pattern on the block that the rubber insulators bolt to, has a different pattern.

These engines also have rounded valve covers with no holes for oil cap/smog valve and an oil fill tube on the right front side of the engine.

 

When the scrap prices went up, most people sold off all the "junk" they had setting around. We have a few contacts that are ford lovers and they all said good luck finding a 460 or 390. There is always ebay etc… and I check CL all the time in and around our area. Heck finding a Pre 79 ford in half decent shape is difficult. Most of the younger generation wants the low honda thingy's around here, LOL We see a lot of old fords out towards the west, but its a long way from VA.
We have the 351m and 400 available and running, and eventually will find a 460, (which is what my husband really wants in the truck).
So I guess we will just have to take it step by step to modify one of these to fit. Just are not sure which way to go.

 

Check with Flashback F-100's in Reidsville NC - Tom sells used parts (336-421-3979).

It's also possible that Carolina Classics in Durham (800-598-4211) or Carpenter in Concord (800-476-9653) may know of available 360/390's.

 

Great, Thanks for the numbers. I will keep them handy as I know I will need them.

 

True Dat!

Go for the 400. The 351M is a slug but the 400 is a good puller.

 

You can order rebuilt 360/390s via rockauto, ford parts, auto zone, oriellys, Napa, etc. Look harder.

The big box part stores probably won't know the difference between what you order and what you provide as a core so good chance any blown v8 will do.

 

where in va are you im near Charlotte NC and see fe stuff for sale pretty often and prob have some of the 351 parts u will need if u do go that way