1948 3100- Need direction on 5.3 year and 6l80e or 4l60e

[uhcoog1]

Trying to decide on a motor and transmission for a 1948 Chevy 3100 project. I know very little about gen 3 vs 4 motors, and I know even less about 4l60e vs 4l80e vs 6l80e.

My preference would be to pick up a pullout 2008-2014 truck 5.3 with 6l80e and run it bone stock.

Will the trans fit okay under the 3100? Is a 4l60e significantly smaller?

I see PSI conversion sells a harness, but they don't sell a 'kit', so possibly I need to source an ECU and pedal? Are the gen 4 motors hard to run stand-alone?

We're using the stock frame with speedway motors suspension front and rear.

Thanks fellas