low compression

In terms of factory heads, the 906 "F" would be the best of the 906 genre. But none are real barnstormers without work. the intake ports on the 516 are flat but it's easy tog et them to move 260-270 which is more than enough for a street or mild race setup. If you throw them out, that's fine too. I wouldnt ask for them, but if I had a choice between building with them and using quench, or running open chambers, I'll run them in a heartbeat. The last set I used made 480hp on pump 91 with a hydraulic cam under .530 lift. It also made 530tq at 3200. They can be made to work, but in terms of hte best factory heads overall, I'll take the 346s for the intake SSR and the exh port.

As for what I'd use on a low compression deal, I would use the 516/915 combo. Because I can unshroud the valves, and not have the dead space by the gasket. Detonation will never be a problem. I'm looking to minimize the chamber size and the dead zone above the block edge. If it was a competition, I'd use a 413 for the stroke but the smaller bore. Of course, using that, i'd be stuck with the original pistons...lol.