6-71 small block build.

I'm just finishing mine up currently playing with the Hilborn injection before taking it to the track. Definitely go 8mm and 3" belt. There's enough pulleys out there that you can just figure where you want to start and go from there. Mine came with 50 & 52 which is pretty lame but that has since been changed. You have to be a little careful because too much change will require a different length belt.