That's when you throw on some AFR heads. But by that point, you need revs to make big power, so you need a good valvetrain and a steel crankshaft and special con-rods.
Or there's always supercharging.
__________________ Proud owner of a '65 289 coupe w/ C4. Equipped with Edelbrock Performer intake K&N air filter, and 600 cfm carb, Comp Cams Xtreme Energy valvetrain, Comp Cams XE262H cam, MSD ignition, and ported heads. Suspended by 600# 1" drop front and stock rear springs, KYB shocks, 1" front and 7/8" rear sway bars, and Traction Master style traction bars. Your friendly suspension kid. | 
