351M anyone know much about 'em

[bobbywalter]

Built 400. Yeah...doable. not for the faint of heart.

Curt can do a detailed data bomb on this. Time. Lots of time.....and money....

And GM parts.

 

[Shran]

Either engine is going to cost a lot at the machine shop. About 10 years ago when my buddy & I were big into late 70's Fords, he had a choice of either rebuilding a 400 that was wore out or using a mid 70's 460 in somewhat unknown condition...we went with the 460... it was a super strong running engine but would burn a quart of oil every couple hundred miles. So he started investigating rebuilding the original 400 or the 460 - the cost was the same, the ONLY advantage of the big block in that case was availability of aftermarket parts.

If I had a blown up 460 and a good 400 on hand, and no smog checks to worry about, I'd be tempted. Pros & cons to both. If you rebuild the 460, you are in for shop labor & parts and a smog choked stock engine rebuild OR a bunch of time & money into tuning an EFI 460 to run right with performance parts or the additional cost of a FiTech/Sniper/etc. Using that good 400 with aftermarket EFI and trans controller could be a sweet running rig, and saving a lot of money at the same time. But it really just comes down to what parts a guy has on hand.

 

[Snoranger]

Yes, Ford made a few 4V intakes for the 400. They were never sold to the public. They were only used for testing and “destroyed”. Destroyed back then almost always meant that someone got their hands on them and smuggled them out the back door.
I actually had my hands on one years ago. It had an XE casting number. Ford XE castings we’re preproduction experimental or test pieces.

 

[rusty ol ranger]

Aftermarket transmission controller should have you all fixed up... the hard part of doing a 351M/400 to 460 swap was clutch components and motor mounts, I think (been a few years since we did one) but going the opposite way should be pretty easy. I think I'm with you, I would rather have a built 400 than any stock 460.

This topic reminds me that I've seen a couple Super Duties with 300 six and 6.9 IDI's swapped in... kind of hilarious really.

I wont lie a 300 SD IMO would be pretty cool just for uniqueness. The 6.9 too.

Anyways...yeah i know about the aftermarket controllers. But being a 97 id have to deal with the speedo and all that shit being electronic too. Atleast i think. I dont know. Its been an idea i floated around for a while. Put an aftermarket EFI on the 400 and with the goodies id lay money it would pull harder then the current 460 and maybe pick up a MPG or two to boot.

I wish ford woulda stuck with the 400 up into the 90's instead of the 460.

 

[bobbywalter]

The 400 is definitely capable of monstrous torque. I have seen many examples..
Once oiling is addressed reliability long term goes up.

In a fullsize truck pushing 6 pounds of turbo air through a 300 seems a decent way to be different these days. It's too cheap not to do really.

 

[franklin2]

Yes, Ford made a few 4V intakes for the 400. They were never sold to the public. They were only used for testing and “destroyed”. Destroyed back then almost always meant that someone got their hands on them and smuggled them out the back door.
I actually had my hands on one years ago. It had an XE casting number. Ford XE castings we’re preproduction experimental or test pieces.

I figure they found out there was no need for a 4 barrel. I just got a 1971 LTD with a 400 running for a guy. 3 speed c6 with 2.75 to 1 rear gears. You would have to go over 100mph before you could get a 4bbl to open up with those gears. Nice highway cruiser though, rides nice and doesn't need overdrive to keep up with modern traffic.

 

[rusty ol ranger]

I figure they found out there was no need for a 4 barrel. I just got a 1971 LTD with a 400 running for a guy. 3 speed c6 with 2.75 to 1 rear gears. You would have to go over 100mph before you could get a 4bbl to open up with those gears. Nice highway cruiser though, rides nice and doesn't need overdrive to keep up with modern traffic.

My 77 LTD II has 2.50 gears.

You could peg it out in 2nd

 

[pjtoledo]

Im guessing most have been extinguished from junkyards.

FB marketplace usually has a decent amount of them though. Atleaat last time i looked.

I had a 78 F350 with a 400 that had the mods i mentioned above. Coupled with a T18 4 speed. That truck was an absolute monster.

If there was a logical way to do it next time the 460 in my 97 takes a dump id put a 400 in.

You got a chassis in mind for it or just wanna do it for the hell of it?

I still have the 351M from my '78 Bronco.
the Bronco needs, ahem,, some work