Are the current pistons below deck and by how much?

I agree on the valve reliefs I just checked a extra KB hyper vs the icon forged for the same basic application and the hyper is about .040 deeper. And with this being a small bore piston im getting a rough approx .040-050 thickness to the land. However I use these KB399 domed in my bracket car with a 150 shot ramped and a top gap of .038 with no issues.

Now the Icon Forged with the same 3.950 bore I spray 250 on ramped with a top gap of .028.

Never an issue with either.

I think you have a lot of options going forward, Id almost look for a proper oem 340 rotating assembly and sell the crank to someone else trying the old school mini stroker trick.

I snapped a few pics of the hyper vs the IC Forged and yes the hyper with the oem ring setup is just middle road over a stock cast but they dont make any high compression 318 cast pistons although even stock cast pistons can last and take some abuse.

This whole ring gap is nuts on the hyper and most just cant force themselves to put a mild motor together with big or bigger then poweradder gaps.

What I find interesting is there is some great lit. out about how big a ring gap can be and still work.

A first hand example I can share is in my youth I took a sd455 and re rung it with a simple hone job, it had .0055 bore taper. I used oem shelf moly rings and it never smoked or burned a drop, think of the gap change with over .005 taper so what the gap would go more then double oem?

None the less the lit, showed a minimal power loss with the bigger gaps, they said 1% over a filed set. This article was in engine builder mag and had info from oem ring makers on what some of the high limits were for some older stuff we use.

I snapped a few pics of the hulking hyper vs the ICF although the Icon is a stroker piston but both a 318-040 bore.