I have a 1988 F250 w/ 302 engine, C6 tran and 10.25 (3.55 ratio) axle. Over 280000 miles w/o any rebuilds. Engine is showing signs of serious wear. Tran and axle seem OK. Box and cab are seriously rusted.

So I found a wrecked 1994 F150 with a reman 300 I6 (has 20000 miles left on warranty) and an E4OD tran, 8.8 (3.08 ratio) axle, box like new and cab has just a few scratches. Frame is bent from accident and front sheet metal is trashed. $500 for the whole thing!

My plan is to switch the 1994 cab, box, engine and tran to my 1988 F250 frame. I just use my truck for handyman stuff and would like better gas mileage. I do occasionally haul landscaping materials and other heavy stuff, so I like the F250 suspension. I run 235/85/R16 wheels on the F250.

Is it a good idea to put the 300 engine, E4OD tran and 10.25 (3.55) axle together? Looks like I'll have to change motor mounts and tran support crossbar, but I can't see anything else major I need to change except the driveshaft. As I measure it, neither the F250 or F150 driveshafts will work (they are both too long). Is there a stock driveshaft for this configuration? Should I keep the C6 tran instead of the E4OD? Do you think I'll get better mileage? How can I calculate new engine RPMs at various speeds with this setup?

 

you would have to move over the entire wiring as well because the e4od is electronic controled tranny. personally since your towing i think youll find that you will get about the same mpg as your 302 or a 351w which could also be swapped in.

the c6 is a strong tranny and runs about 600 bucks if it needs a rebuild but only 3speeds. the e4od is fairly strong but can cost anywere from 1600-2500 to rebuild but has 4speeds. but i think with the weight of the rig and towing a lot 4gear would never be used. the 300-6 has better low end torque then the 302 for sure but gearing would need to definatly stay at 3.55. the 3.08 would be a dog.