He's using Edelbrock heads, not TP heads, or SOHC heads. I have seen the tulips improve flow starting at .400" lift over the nail heads, in many Edelbrock applications. I have been installing 2.150" or larger intake valves made by Ferrea or REV or SI since the early 90's, and the 45* angle or greater always increases flow above .400" lifts. I have taken a set of 390 C6-R heads and cut the seats for 25*, 30*, 35*, 45* 50*, and done multi-angle valve jobs for these angles, and flowed each to compare where the flow increases or changed. The nail-head with 30* is superior at lower lifts, but quickly loses to the small tulip or tulip valve above ~.350-.400" lifts. I stand by my answer, that valve will work fine with the 45* seat in the Edelbrock head. Joe-JDC
