I have a92 G20 350 700r4(i think) dana 70 with powerloc rear 4:10 gears. This is my tow rig for around 8000lbs. I want to swap to a th400.have the trans and the ability to swap mounts and driveshaft. What else is involved? Thanks

 

A 1 ton truck...lol. 8000 lbs is more than a 2500 is rated for.
I think you have a 4l60. Basicaly the same thing.....92 was the year it switched to electronic shifting, (4l60e), so if you have that then a switch back to the th400 would be an issue.
If you rebuild what you have with a shift kit, and an aux cooler you should be okay, but that is a lot of weight for a 3/4 ton. My 2002 2500 express is only rated for 5800 lbs towing....

 

Agreed, towing 8000lbs with a G20 is just not a good idea. G30 is what you need. Its not just the rear end and trans.. brakes, springs, shocks, tires.

 

I would also add that the 350 although is a great engine, is a bit underpowered for that kind of hauling. You need a big block or a diesel.....
I would look for an old g30 with the 454 and heavy gvw.....then fix it up..