Thanks for the responses. I ask because I have a lowly 383 and I am putting portted sidewinder heads and a tr on it. But my future plan is to build a bigger short block eventually.
My current combo is 12.5 to 1 trw domes, mp590 cam. 2800lb valiant. I'm hoping at least 10.7s. But eventually wanna build a short block for 10.00 or better. Looks like these heads can do the trick.

Last edited by viperblue72; 12/16/16 09:44 PM.