I have an 89 E-150 inline six 4.9 which runs great.

I'd like it to be able to hold more cargo weight without concern for wear and tear over long time.

Parts and labor are cheap and abundent where I live.


Can I put a used rear end from an E-250 or E-350 into my E-150 with ease? I imagine I must change the rear springs as well?

Is the drive shaft the same length/size?

The van will be used for highway driving mostly (no towing, just cruising)and I'd like to have the highest possible gear ratio to increase gas mileage.

All help is appreciated!

 

First - you don't want too high a gear ratio or the engine will be lugging. A good rear for a six is a 3.08, but a 3.25, maybe 3.50 for highway miles would work. You will want to check spacing between leaf spring perches between the axle shafts to be sure the new axle will fit up there. Then check from imaginary axle tube centerline to axle front where the driveshaft mounts and be sure lengths are very close. You may want to use your axle springs or get some heavy ones custom-made because a lot of times the individual springs don't match up (measured off the van - center of bolt hole eye to bolt hole eye). Keep in mind if you don't have an overdrive transmission you may want to get one. It will give that extra high gear for even better fuel mileage - let allow you to keep a lower rear ratio for the heavier duty jobs.

 

you are also looking at a five lug bolt pattern vs. an eight lug