Here's an interesting dyno shootout 160 cfm head on a 306, 333 & 393.

Here's an interesting dyno shootout 160 cfm head on a 306, 333 & 393.

The 160 cfm heads made 1.91 hp per cfm on the 306 (306hp), 2.2 hp per cfm on the 333 (352hp) & 2.41 hp per cfm on the 393 (387hp).

They all had different cams, got larger as displacement went up which would also be contributing factor.

Be kind of like if we did a 318 vs 360 vs 408 with stock 318 heads.