Can anyone tell me about my heads with casting #993? I just bought a car with a set on it and i'm not sure about the specs (intake runner, valves, chamber cc, etc.).

 

Good heavy casting with very few failures. Can be found on GM Targetmaster replacement engines.

1.94/1.5 valves but can easily have 2.02/1.60's installed.

74cc combustion chambers.

Technically they're a smog head but the casting is one of the better ones to have. Some bigger valves and some port work can make then good performers. The 74cc chambers allow for bigger valves that won't be shrouded. Increasing compression will mean having to change the pistons.

If I was every going to build another SBC with cast iron production heads, those are the ones I would use.