Did you have the heads resurfaced before assembly ? (not reading 52 pages for that info lol) Just sayin', if they were raised in the center even .005 that wouldn't help the 8553's out at all either
There were the heads that came off of my duster when I put the speedmaster aluminum heads on my duster. They had been previously machined...
They probably had less than a couple thousand miles on them on the duster. They were completely rebuilt by the machine shop when I originally did the stroker for the duster. K-line valve guides Crower springs chromoly retainers 202 valves... The works and always perform flawless in the duster with 1008 head gaskets LOL...
I really didn't think much of it when I put the 8553s in there...