They are GT40P heads. They were new castings, not installed on an engine. Stock bolt down stamped steel rockers. Flat tappet hyrdaulic cam - mild for low rpm torque. No studs - bolt down - so no adjustment other than pushrod length. Springs are stock springs for 1989 351W with flat tappet cam. I'm changing the ones that were on the heads as they had a higher spring rate since they were meant for a roller cam. They were aftermarket springs as they didn't have the exhaust rotators installed like the stock heads.

I'm going to pull the heads off, and take a valve out and measure the overall length to compare to the standard valve for this application. I guess I just don't trust what's there and need to know for sure.