Yeah the valve to piston clearance was probably just super tight. So it spun over by hand but had problems when the guy ran it out the back door. The original engine builder messed up the piston install and then he must not have bothered to check valve to piston. And evidently nobody else ever checked VP even after the problems they ran into.

I don't think the article said what heads are on the engine. I'm guessing they are either EZ or SR heads with an Indy dual plane intake? If it is screwed together correctly that combo should make 600+ hp.