Piston Class is in !!

AJ/FormS said
I'm more confused than ever

OP said 340RPM heads.
With the .060 relief cut
To make room for the nominal, +.045pop-up, 340 domes.
leaving .015 clearance..... plus gasket thickness
is about .054 with an .039 FellPro, or .045 with the .028 gasket.
mathematically speaking.

Where's the problem?

I saw several comments over the internet and even Cambell Performance list the dome piston for oem heads and said the dome want work but why would Edelbrock even incorporate the extra clearance if it wasnt for the old Heavy slugs once sold for the 340 engine ???