Well, i can't say what it's worth in HP, but my increase from 11.25 to 12.50 was worth 4 tenths and 4 mph. I will be honest and say i also ported the intake plenum and added an electric water pump as well, so not apples to apples, but the hp gain is much more than some may think. I try not to leave anything on the table anymore with my street/strip set up.