Flat quench area is old thinking for 30 year old small blocks. These 4 valve per cylinder heads have very little quench area and focus more on cylinder filling and air movement into and out of the head more than just old fashioned squish. Believe me, these heads and chambers flow more than small block race heads with very little porting!!!
It's not the heads that are holding these engines back, it's mostly the physical strength of the stock parts that are hoilding big numbers down. Replace the rods with aftermarket ones, then replace pistons with lower CR ones, you're left with a crank with it's power limit of around 400-450 HP (at the crank) if it's going to last at all. Drop about 3 grand and you can have a custom billet crank, then you can really take advantage of some low CR pistons. Otherwise, the only reason to lower the CR is to increase your margin of safety against detonation, not as a power increase.
