What belt would you use?

[SVTVenom]

What belt size/# would you use for the 2.80 pulley and a 4lb lower pulley? I know a guy that has this setup along with Cat X-Pipe, Flowmasters, MAC CAI, Diablo Chip, and a NX 50hp Wet Shot. He is putting down 504rwhp/612rwtq even with an incorrect belt!!!!!!!!!!!!! :rolling:

 

[matt lankford]

I have a 6lb and 3.10 going on tommorrow with a 79" gates. the lower pulley is supposed to have a adjustable tensioner that you can tighten up. mabey he should try that