I have seen some icon/KB pistons for mopars with HUGE valve reliefs. If you go to piston details , icons site says how deep the reliefs are.
Isky used to rent flycutters. Ive seen someone selling them recently too. We did a homemade pair, a few years ago. Welded a carbide cutter to an old intake and exhaust valve. Turned out we only needed a small nick on the exhaust side of a cast piston, to get a 312 .590 purple shaft in it. Ran surprisingly well for a low compression engine.
