I had plenty of low comp small blocks run way better than most people would think they could. Example: My brother's 68 Valiant, his only vehicle at the time, running the exact 1/8th mile times as an ls6 Chevelle. Ls6 had open headers 4:10 gears, Danny had full exhaust and 3.91 gears. Ls6 had slicks, Danny had used dirt track tires.
The Ls6 guys kept coming over and looking at the small block and shaking heads.