This is the third time I've reworked this engine. the cylinder heads have been the problem each time. I'll not use the Speedmaster/ProComp heads again.
The first time the head problem reared it's ugly head was when the engine began to smoke after installation. We drove 600 miles one way to the car to do a compression and leakdown test. All good, but plugs oily. Pulled the intake manifold and found oil leaking into the intake port from a bolt hole sleeve we had to use to correct a casting shift found during porting. Drove the 600 miles back to the shop and ported another head, loaded it up and drove the 600 miles back to the car and installed the new head and drove 600 miles back home. All on our dime.
Better but it never fixed all the oil smoke.
We told the owner we needed to find out why it was still smoking and he drove/raced it around for 2 years and then brought it to the shop for us to remove and tear down. Found the other head had a hole in the rocker shaft bolt hole. Tore the engine down and reringed it and installed the iron heads, fiddled with it and made 620 HP, all on our dime again!
Bent valve? The owner is a heck of a nice guy, but I ain't paying this time.