Headers used with Speedmaster heads
I put together a index of the Speedmaster threads that have been posted lately. Lots of good information.
@318willrun will be taking his stock heads off and installing his Speedmasters for a comparison. I don't know if anyone has done that yet unless it's in a older thread. You may want to search "Speedmaster" and see what older information you come up with.
Speedmaster head thread index