Al, I use the same set up. It should be pointed out that 10 seconds is not a "golden rule". Using a temp stick, the difference in time required between a 223 Rem case and a 223 WSSM case is (much) more than 10 seconds, for example.
Yep...neck thickness, etc. all plays a role. I'm going to check the next batch with the digital temp gun we use on the dyno to check header temps.
Good shootin'.
-Al
