You probably don't want to hear this from me ... but tear it down

The engine was run , not sure how long mine had black residue in the exh ports.

I have a 426 , the ID of the springs are about .090 bigger than the retainer step , the valve guide clearance is all over the place , I think my heads have bronze liners now.

the head gaskets have red RTV around the the big water ports, mine had RTV in at least 2 cylinders they put on so much. The #1 exhaust pushrod rubbed on the head gasket enough to keep the lifter from rotating when I spun it over by hand. When I matched the gasket to a steel shim gasket the exh pushrods holes were not in the exact same spot and they were both felpro gaskets.

All the ring gaps were lined up over each other on at least 5 pistons , not sure how much that matters though.

I never checked rocker geometry , After seeing the pushrod and spring issue I pulled the heads and found the head gasket issue so I just tore it down to a bare block.