In the quest to complete my 70's crew cab conversion, i just inherited numerous projects and therefore power options.

My current truck is a 1974 f250 Hi Boy that i made into a supercab. It is powered with a 390 and 4 speed. I am wanting to stay with gas but want to make this my everyday driver and pull/haul anything truck.

The options i am looking at: 390, 391 or a 460. I have them all. The truck has a divorced T-case so that is not a problem. I know of most power adders but am not wanting to stroke because i am looking at adding an STS turbo in the future.

Also have the option of C-6 (for both 390/391 and 460) or truck 4 speed. Keep also in mind that i am looking into the different gear splitters/overdrives.

So many options i thought i would throw it out there for your input. Keep in mind that i have all the engines/trannies i talked about.

The 391 is new to me. Through my research i have found that the block (and lower end) is bulletproof. The whole top end, not so good. But i have all the 390 stuff to put up top. Maybe even buy some CJ heads and intake to really juice it up.

All of the different combo are swirling around in my head. Too many options!

 

The 391 is a FT motor and not really a good idea for a regular truck. It was designed for Uhaul type application and such.

But you can use the 391 crank in a 390 FE, but I am not sure of the cost to modify it. If done the 391 is some type of forged steel, and is still probily cheaper then a aftermarket piece.

So the 390vs460 debate. I have had both, and both are good motors when set-up and would consider using either one.

I would go with the one that is most complete or in better condition or which one has more aftermarket parts cheaper in your area now.. Rebuilds should be about the same cost so for me it would come down to the cheap speed parts availibility.

 

Well, the 391 is not gonna be worth beans as a daily driver, the lower end is bullet proof because the engine never revs much past 3500 RPM (I used to drive a fire truck with one of these and it was a pig at best) and doing that makes almost any engine bullet proof. The 460 will have gas mileage that sucks at best and will not out preform the 390 by much if at all. Stay with the 390. Trans wise, the C6 is easiest to drive but the 4 speed will get better mpg, however the truck 4 speeds are not very smooth. For a daily driver the stock 390 heads are more than adequate, CJ heads will hurt mpg without really improving usable performance.

 

390 4speed gearvendors OD and drag the house away. Since you're not going to be hotrodding or anything that tells me mostly stock. And givin that, I'd take the 390 over the 460 anyday. 391 is a tortoise... yeah they live forever, because they move reeeaaall slloooww.

 

Be aware that besides the FT 391 4V, there's also the FT: 330 2V Medium Duty, 330 2V H/D and 361 2V.

Just like FE engines, all FT engines look identical.

 

So it's down to 390 vs. 460. Do you have 460 mounts and tranny/bellhousing for the highboy?

 

Of all the stuff i have around here, the one thing i dont have is the bellhousingfor a 460/4speed. I have about decided to keep the 390 in there. Its not 100% though. Just leaning that way.

From what I have been reading though, I think I am going to leave the 391 alone.

 

FE's are starting to go the way of the Y blocks and flatheads. I'd keep the FE for the nostalgia factor and the fact that they can make some good power.