Did it go from having no quench to a real quench area with the milling? If so, I'd think that would have something to do with it needing less ignition lead.
Did the BSFC numbers improve, too?
This is what I was getting at. .040 compressed head gasket?
Just looked and saw RAMM got a 6% increase, much higher than the Vizard chart I posted predicted. I suspect he found some "bonus points" by building quench into it, too.
Well, RAMM?
Yes as I have stated many times over I am a BIG believer in quench. Because Mopars suffer so badly from basement level piston to deck heights from the factory this serves as a prime example of getting it "right" and can and does reap excellent results. Also in play is the extreme reduction of "crevice volume" I believe quench and crevice volume share an extremely close relationship. Yes the gasket is a true .039" compressed thickness--I reused them BTW.
The BSFC's did improve by a remarkable amount. They are low to mid .4's as of now. I also believe that the intial "suck" on the intake port is a touch better with the closer relationship with respect to the intake valve/valve pocket--This is why minimum valve to piston clearance can be a power maker. J.Rob
