Ok let me start out with this ,I know a lot of you out there love your 351/400's! I don't I love the small blocks302/351w and the 429/460! So I'm not gonna rag about them to much,but I bought a 1978 f250 supercab 60's front and rear 4 speed all in all a good truck 32,000 on a NEW 400 ! well when I got it it ran like a turd! so I fixed all the dumb *** things he did and got it running pretty good. Well all was well till the other day started running like crap after about a 20 mile drive checked all the obvious things nothing! so here's my question 460 or 12 valve cummins I have a dove-a block and heads that I can build or I can buy a donor truck for the cummins I'm leaning toward the cummins for mileage and power I tow a 26 foot camper a lot ! I know the power of a 460 is awesome but the problem I've always had was in the trans the 435 has to much split between 3rd and 4th and they fall on there face on a pull ! I'd really like a 5speed and a cummins you guy's let me know what you think!!!!

 

I know where you are coming from. As soon as I read the title I knew a 351m/400 was the modivation for it. Just like you said some people love them but what I've seen of them in person (not from stories I hear), I think they are the worst V8 ever made. Ha ha.

As for as which way to go I guess that depends on how much you want to spend and how much work you want to do.
I'm not much of a diesel guy and I love the big blocks but if you tow a lot a Cummins is gonna be better for that.
Now it just comes down to money and amount of work like I said above.

 

Cummins all the way. 4 MPG with a 460 BLOWS - hahahaha

 

If the money is there go with the cummins, it'll be faster and get better milage. Then again I'm kinda biased after having a 7800lb 4wd that would run 13's in the 1/4 mile and get 23mpg on the way to the track and back

I like the 460 in my F150, but if I had a f250 or bigger it would be a cummins for sure.

George

 

Ok guys I'm a very decent fab guy can do about anything I want ! so lets git with figuring out how that cummins is gonna fit in there just towed my trailer home with my kids dodge and I live in Idaho 5th gear all the way home and got 21.5 miles to the gallon! so tell me what i need to do this! thanks guys

 

Something like this???

https://www.ford-trucks.com/forums/7...-crew-cab.html

 

For starters, start looking for a decent donor prospect. Buy a wrecked or falling apart body truck, the engines are good for 500K plus if they have had any kind of love over their lives. Buy the whole truck, not just an engine even though it may seem like a swinging deal at the time. You will save hundreds of dollars on all the small parts, and thousands on the big ones you will use. In my opinion it is best not to reinvent the wheel. Use the Dodge transmission and save hundreds you will have to spend on an adapter to use a C6 or ZF transmission. I used a ’89 as my donor, but if I had it to do over I think I would look for a ’94-97 as a donor and use the engine/transmission/transfer case. (’94 Dodge changed to a driver’s side drop transfer case) Next, start looking at some of the galleries and write ups of guys that have done this swap. I would point you to mine, but I haven’t taken the time to do one. I didn’t click on the link ChaseTruck posted but I think it is his build thread which has some excellent pictures and ideas. I have had my truck done for a couple years now or I would shamelessly copy some of the things he is doing. Look at users Scot and jnorby gallery. Both have excellent pictures and descriptions of the steps they took. Without them my truck would still be a basket case.

If you do all the work yourself, you can do this for little money. All told I have less than the price of rebuilding the 460 I replaced after selling the axles from my Dodge and the 460 and transmission from my Ford.

 

Sounds like you made-up your mind but if you want even more reason to go with a 12v.

The last 460 I had was a 97' efi 3.07 rear. LOOOOVED it! but it got 13mpg at 75mph empty on an interstate with no stops and a tailwind. NO JOKE! I like some of the fellas here am doing a Cummins swap on a 78' F350 Crew as we speak.

 

7.3 powerstroke. It came in a ford anyway. I get tired of all the cummins

 

Hey now ford uses cummins too so it is an option if you need another reason

 

OK in a small truck I was meaning

 

lol Its ok although I wouldnt mind puttin a 6.6l dual turbo cummins in a 78 350 dually

 

He want's it to work and get good MPG, my stroke does niether.

 

My stroke does both and real good at that. I work it as hard as a truck can work and it loves it.

 

Mine works great and gets ok mileage.

But back to the point. If you can weld and fabricate even crudely you can do this swap. I think jim threw out some good points and definetly check out chasetruck and hrdrokn's threads. The 1st gen cummins (89-93) seem to get better mileage but don't put out as much power they also have a weaker 5 speed (getrag). The 2nd gen (94-98) are good on mileage and have unlimited power potential ( depends on what you want to spend) and have a decent 5 speed trans (nv4500)

Let us know what you decide.