ericjon262 wrote: I'd like to see how he drives the reversed heads cams.
I think the Radical and the couple of others I've seen just use a timing chain at each end of the engine.
An engine like this using Honda K-series cylinder heads would be a monumental beast... but I4 engines for cars tend to have very small bore centers, and thus need a lot of stroke to get decent displacement. This makes the engine highly stressed at high RPM.
But I don't know of any modern I4's which have a decently large bore center like the Quad 4 or BMW's S14.
Nissan has had a 2.5 I4 on the market for a while, right? I've been generally impressed with that mill when renting Altimas. I'll have to look up the bore and stroke. Anyone know how well that head flows?