To get 10.0 compression in a 383 with a stock stroke you need a flat top piston with NO VALVE RELIEFS that is stick .020 ABOVE the deck , .021 steel shim gasket and a head with 79.5 cc combustion chamber volume .

There is no longer rod available off the shelf that would move a stock type 383 piston up to get quench .

Cheap and easiest way to achieve quench ... ... is to use a closed chamber head .