Ive read alot recently about the flat top pistons. Truthfully only way to know is to check the PVC. And probably notch the pistons.. But, some have commented they have been able to clear with E7 heads some with a small cam change.. TW heads will clear Ive read.. BUT, has anyone actually bolted a set of gt40/gt40p heads and cleared? Any with gt40 heads and roller rockers?? I'll no doubt have to check myself.. but if some people have cleared.. it would give me hope!