Edelbrock heads on a 340 with KB243 pistons

Is that page from the Direct Connection book? What page?

FWIW, a few decades ago, leaving .100" from coil bind for max valve spring compression was published commonly; now I see .060" all the time. And quench gaps of .040" or less were well known 40 years ago. So the above .055" piston to head clearance is pretty conservative.

Now if you get a crappy set of recon rods like someone tried to sell me, with .029" center-to-center length variation, then yeah, you had better push that up to .060" or .070" clearance. No, I rejected those rods LOL