Who is running the highest dynamic compression ratio (DCR) on pump gas 93 or 92 octane?

I am thing of building a 383 with KB -7cc pistons. Zero deck height, a .040" 4.06" copper gasket and PROTOPLINE 64cc heads, i haven't actually measure the chamber size yet. I will be using a comp solid roller XR274-12R cam with 274, 280, ground on 112, 108.

I calculate a 8.696 DCR, which is pretty damn high!!

Should i build it with different pistons?

I think i might do some valve unshrouding to open the chamber to 67cc or so. But i don't really want to grind on my new heads just yet!!

 

That is cutting it close. I hope your talking about alumium heads.

All this "dynamic compression" is really a bunch of whooy.
Why buy into the " cam it big and you can run more compression."
An efficient motor with less compression will make more power than a over cammed, less efficient motor with maxed out compression.
Think about it. An efficient motor with good volumetric efficiency will pack a lot of air in the cylinder. It will not tolerate as much compression as a inefficient motor say with a head that flows a lot less but with the same camshaft. Or an under sized carb.

You can't compare your motor to someone elses.
It is bad/ risky engineering to try to get the absolute
most compression out of it 'cause the conditions that you'll be useing it under will change. ( weather, operating temperature,
carbon buildup Air inlet tempeture and density, available fuel octane quality etc)
I'd get it down to 10.4:1 or less for alumium heads and 92/93 octane gas.

Opening up the chambers with a little valve unshrouding
and polishing will get the compression ratio to a useable
level and help low lift flow a little.
Just my .02....