roller rocker ?

[fastTa]

I bet you pick up 10-15 HP just on friction loss...not to mention the higher lift of the cam. I have heard numbers in the 30-40 HP range, but thats being really optimistic IMO....

I have seen a few dyno runs with the 1.6 rockers being the only mod to their LT1, and one was a gain of 15 RWHP and the other was a gain of 18 RWHP. So I think it is pretty safe to say that you will gain at least 20 HP at the crank with the 1.6 rockers being the only modification.

Put in a bigger cam and then the percentage margins goes up on the lift.