So my 1990 F250HD (351w, 4 speed, 4x4, SAS, ) is getting pretty tired. They PO was a farmer and he put the truck to work pretty good while he had it. It only has about 95K original miles on it, the frame is still pretty solid, and the body still good on it, so I don't want to just get rid of the truck (only paid $1,500 for it a year ago). So I'm considering doing an engine swap. I want to put a big block in it, but I don't know what motor I want to put into it, exactly. I've considered both gas and diesel motors. I've never heard much good about the 6.9L diesels though, and I don't really know how big of a headache it would be to put a diesel in the truck because I don't have much experience with diesels. With that said, I'm thinking maybe a 400m, 429, or 460. What do you all think?
Any input is appreciated.

 

A carbed 460 is a pretty straightforward swap for the setup you have.

 

what would all need to get done for that? motor mounts, different bell housing, hook it up, and go?

 

Adaptor motor mounts (L&L), bell housing, fuel pressure regulator, headers and a 460

 

I'll second that. A carbed 460 is a great combo. But you're going to need a new trans, motor mounts, all of the external accessories for the engine, maybe a cooling upgrade and the engine its self. It's very doable and worth the time but it is a little involved. You could also think about stroking the 351. A bit more stroke with a freshen up top end will be a great improvement over a tired small block. Plus all the odds and ends to make a big block swap would add up to around the same as a basic stroker kit plus rebuild.

As for a oil burner swap I'm sure that you'll get a bunch of guys that are riding on that band wagon to tell you that the only way to go. I don't think it would be worth the cost. If you're thinking about it though, IMO the 7.3 is the only way to go. It'll cost a lot more and is A LOT more involved to make the swap than either the big block or stroker.

I'm a big 400M fan but for these trucks I'd wouldn't do it. If it was an early truck that already had a M engine in it I'd say build one. For your truck though it would be just as much trouble/cost to swap as a 460 and the big block has more potential.

My vote would be for a stroker in the sub 7 litter range. I'd second a big block after that.

 

That does sound pretty do-able.

My first question would be, why would i need a new trans? I hope you just mean bellhousing because the trans thats hooked up to this was originally hooked up to a 7.3L diesel and I had a guy at a local salvage yard look up the bellhousing that i needed to put that tranny on my truck, and i have the only one that he could find in the state because the 351w never had a 4 speed. so as long as i had a bellhousing i could do that.
See but the reason i was leaning away from keeping the 351 is that a buddy of mine that builds pulling trucks said he'd trade me for my motor, as long as its running, and i could have whatever stock motor I wanted that he's got. (And believe me, the choice isnt slim).
Im also a pretty big fan of the "Boat Anchor M" motors. around here there pretty well known by that title. But like you said, theres more potential elsewhere.
Thanks for all the opinions

 

Okay, I take the trans comment back. For some reason I was thinking that you had a newer truck. When I saw 4 speed I thought 4 speed auto which have integrated bellhousings. In the back of my mind I was also thinking that even if you misstated 4 speed manual for 5 speed manual then the trans comment still applied because the ZFs had their bellhousings integrated also. But you’re right. If you still have the stock T18 then yes you should only need a bellhousing and matching clutch assembly.

And I learn my lesson. Read the post twice before making comments

 

Ohh okay. See I guess I should've stated that my transmission set up is pretty unheard of. The nice thing about it though, is that I can hook up whatever motor I want to it pretty much. Which is why this has become such a debate in my mind of what to do with it.