I am the current owner of a 1999 ford f150 with the 5.4l v8 and auto transmission. I just drove it from Tucson AZ to Connecticut and Had a max of 13 mpg. I want to do a diesel swap for power and economy. I know a 4bt is possible, but I'm looking for a little more power than the 4bt can provide. Id like 400/800 once all is said and done. whenever I do the swap I would do a SAS from a 2006 f250 t handle the extra weight and power. My favorite option is buy a complete donor truck for whatever option I choose from these: (open to suggestions)

6.0 bulletproofed f250
any duramax pre 2008
any cummins pre 2008

I like the duramax best because it is the lightest and smallest option of the three. and people see a decent fuel mileage from them too.

If I got a complete donor truck I would transfer ALL electronicsfrom ecu to tcm to dash wiring harness and guage cluster so that way any tuning available I can just choose from that vehicles aftermarket support.

What frame modifications to handle the extra power are possible. not much info on beefing up the frame.

What other options do you all suggest?

I want to make this a good road trip vehicle that gets decent MPG and can tow a car or maybe an off road toy and also not be too huge to be an off road toy itself


Final expectations:
400/800 power
dana 60/sterling 10.5
8-10 inches of lift currently 5 or 6
38-40's for tires (currently 33's)
20-30 mpg
decent towing

 

I don't want to just go out and buy a huge 3/4 ton truck that might rode really poorly and have trouble in the woods

 

I don't know if you would be able to put that much power down on a half ton frame without having issues. And having 8-10 inches of lift and 38"+ tires are also going to kill mpg's. Have you given thought on what transmission you are going to use?

 

No way would I bother doing a swap on that truck. Buy a Duramax xcab shorty and call it done.

 

400 hp, 800 ft/lbs and good mileage? Those are almost mutually exclusive. If you are looking for mileage, run closer to stock.

If you are looking for power...it will be much cheaper and easier to buy another chassis with a diesel. On yours, you will have to upgrade: front suspension, rear suspension, front axle (which will entail changing the rear to match), transmission, fabbing mounts, sourcing a radiator to keep it cool then making it fit, source and fab an intercooler, bigger fuel lines, bigger fuel pumps (assuming you have twin tanks, pump if you only have a single tank), shift linkage or clutch assembly, etc. You are looking at a pile of cash to do this. The parts are all expensive, and the "little bits" will nickel and dime you to death.

For a mileage build, I would go with a Mercedes 5 cylinder boosted up a bit with a TH700R4 behind it. Should move an F150 around decently and get reasonable mileage doing it. You can buy a complete Mercedes pretty cheap, so alot of the nickel and dime parts will be there.

Power build? I would go with a 12 valve Cummins. Plenty of aftermarket support, tough as nails, and cheaper to rebuild than the others by miles and miles. (sleeve engine, not a cast bore block like the Dmax and the Stroke.)

Nobody I know running 38-40 inch tall tires gets over 15 mpg. None of them. To keep it from being a slug you have to regear to at least 4.88's, and that murders mileage. I know 1 guy with 44's, he had to regear to 5.13's...his mileage wasnt alot better than my 460 big block gasser. I got 12, he got 13.5 with his 'stroke. for the amount of money we had in the 2 trucks, I would take my gasser ANYDAY over the diesel.

Just my .02 cents worth.