Misfire at cruise, popping/afterfire at 3000RPM

Okay, anyone who said valve train problem was correct. However, that may not be the only issue.

Machine shop says I have broken springs, however the cylinder head guy is out with covid, so Gary (the owner) couldn't elaborate on how many or which springs. He did say that my valves are all sealing and the springs seem to be the only issue. I will be measuring the cam today for lift so that he can install the correct springs.