I have installed several of the GM crate engines and everyone was happy with them. If you look at the specs between the 260 and the 290HP you will find that the main difference is the cam. To get those HP ratings they list a number of components that are reccommended such as headers, hi rise manifold, carb, etc.
I prefer the 260 version for normal operation. Since you have a 4000lb truck (C20 has a 457:1 rear end) and a 400TH trans the mileage is not going to be great anyway. An OD trans like a 700R4 would probably be a good choice.
Fred
Last edited by rfs56trk; 10/20/2013 5:21 PM.
