Re: Not a hemi

Right, I'm sorry George I missed that point you were making. Yes I agree with you that the open chamber in theory could be better than a hemi in that the chamber is more shallow, and better than an inline valve head because flow is better.

I always assumed that an open chamber head would have an advantage in flow over a closed chamber head, due to less shrouding of the valves. If the flow is equal, then I would think the closed chamber wedge shape would generally be superior to the open chamber due to greater detonation resistance and a more compact combustion area provided by the quench pad. However as I alluded to in my first post, all wedge chambers are not created equal. Also, manufacturing tolerances used in mass production of engines circa 1970 might not do the best job taking advantage of the quench features. That would be left for aftermarket performance builds.

I'm still wondering if anyone can compare preferred ignition timing between the two types of heads? I think that provides good insight into how efficient the combustion chamber design is.

Edit: One other thought I had is that you can gain some insight into how good the open chamber design is by looking at how many modern engines use a similar design.