Keep the 460.........in its stock form it is pretty impressive powerwise as it is, but its has not even begun to scratch the power potential that can be achieved with a little work.
10-13 mpg is all you will ever get, face it......its a heavy duty truck.

 

Swap to the diesel... I get 21mpg from my 7.3 PSD, makes 400hp, and has 320k miles w/ ZERO issues at all and I still drag race it. This is how I look at it.

With the 460 you will run into limits of the stock EFI and have to do a bunch of rewiring and such anyways if you ever want to think about making power. Now you might see close to 300hp from the 460 w/ head porting, TB, headers, exhaust, intake, etc.

7.3L PSD- You will get good mileage with this engine all day long(depending on lift and tire size). 18mpg would be pretty normal for a CC LB 4x4 w/ a lift on 35's. If you swap it over to a manual trans at the same time then you can make plenty of power without ever having to worry about the tranny going south like you will with a modded engine and the E4OD. Performance will come much easier from this power plant also. It isn't hard at all to pull 400hp from this engine w/ mostly stock components. Probably be easier though to just get rid of the truck and get a whole different truck with a diesel in it already, but there are several guys on this forum who have done diesel swaps from gassers and they love them.

 

+1 sufferingiant. The cost of switching over to the oil engine will be far greater than the extra couple hundred$ for gas. A longer stroke on the 460 would be nice, though.

 

Thanks everybody for your opinions.Still sitting on the fence. I have a buddy that works at ford thats comming out to check out the 7.3 to see how it runs.

 

7000 POUND TRUCK + YOUNG male driver + big block ford = 4mpg

i mean my f-150 5.0 when i first got that thing i damn neer broke that throttle cable i hammered it so much.... then... gas hit 4 bucks a gallon.... i started driveing properly... go some pullys headers a cherry bomb one of the drop in filters and a home made air box... went from 9 hammerin it to 19 highway but its more like 17ish because well im still a young male

 

LOL If I hammer my PSD quite a bit I will get like 14-15.. Yes, I just said that. I like hearing the sound of a turbo spooling. If I put it in my econo tune(where even if I hammer on it then it doesn't smoke and probably has about 240hp) then I will get 18 if I hammer it a lot. Put me on an open highway, I'm not in any hurry where I can cruise at 65mph and I will get 21mpg..

 

I agree with the powerstroke mileage. I have 02 F350 CC 4x4 7.3 great mileage. Even better chipped. When my son was driving it same as he is driving now with his 460 it alot cheaper. but if I go with the swap how much work is it remember we are going to change the front clip anyways.Will the doner truck have eyerything needed. Will the wiring harness fit.