You don't need a lift to run the 8.1 with a 4l80e trans. There is a youtube vid of non lifted 2wd Silverado with an 8.1 and a NV3500 spinning the tires pretty good...

 

How much does a low mileage 8.1 run for anyways?

 

Yeah, it looks like the 8.1 will take the place of the 6 nicely right in front of the current tranny with no lift. Unfortunately I can't afford the allison, but if I had the cash I would get the duramax along with it. Then i would need the body lift!

Depending on which one I go with, it looks like I can get the engine for between $1200 and $1600. Mileage is the main difference. I think the $1600 one is under 100K, maybe around 67.

I may not be able to wait much longer before I decide though, but i have no choice, I have to wait at least a week to see what the funds are like. I was pulling a 17' trailer yesterday and and when i parked it, could really smell the oil, and there was smoke too...

What do you all think about buying engines off of ebay?