Thanks much for the information once more. I am about to procure a set of 360 high swirl heads from a friends stockpile of HD Dodge parts, I am hoping to luck up find some early ones without the huge pushrod boss. Planning on the largest size valves practical to minimize the chamber volume and working the ports for maximum flow under the .530 lift range. This will be going on a 3.94 bore 318 (.050 over if I go to dome pistons). If you don’t mind my asking, what would be your recommend valve diameter and seat angles on a set of these heads that still have the factory cuts? They will be getting a Serdi radius job.