[mgarblik]

Originally Posted by steve25

The problem with original Hemi heads heads in relation to timing needs is the total lack of squish.

And if you do get the piston dome near enough to the chamber walls to generate some turbulence then the flame travel goes to Hell in the Hemi head faster then the added timing can make up for!

Just go look at the power improvements in the aftermarket Harley heads designed for squish.

Dead on target and the reason the hemi heads work so well in racing and not so great in low RPM, street engines with emission requirements. Racing engines: High RPM, high flow, low turbulence, hemi is perfect. Especially true on nitro where squish and quench=explosion and severe detonation. Usually, when I say this, a Mopar nut will say, "then explain the modern hemi" The modern hemi is a "Hemi" in name only. It is really a 2 valve pent roof chamber. It has both a quish and quench pad. Small, but they are there, unlike the original Chrysler Hemi design. They are needed for mixture motion, turbulence, low speed driveability, emission control, primarily, HC emissions from the dead space created by the hemi shape.