I run the Comp Cam roller rockers on a big block Chev, and they are 1:7 to 1. You do not want to run the big block rockers on a small block engine because you may develop enough extra lift so that your valves start kissing your pistons. This is not as much fun as kissing at the drive-in, and can be more expensive.
Bob


55 Cameo 396 TH 400 with overdrive
65 Caliente conv
67 BB Caliente conv
67 Mercury 1 Ton
76 GMC 3/4 ton 454ci
84 Buick Turbo Regal