You might have to adjust other things a bit as well after zero decking I would think. I mean my(iron headed) motor is at 9.7:1CR already. If I zero deck it and leave it the way it is with 75-76cc head chambers I'm looking at alot higher CR. I don't think it would be totally offset by the new quench. I'd have to figure it out but I'd bet it would put me in the 10.5-11 range. It's not going to live on today's pump gas.