Question: what cc are vortec heads?
Answer: “The stock Vortec combustion chamber on the 906 heads is about 63cc's. When we angle milled the heads 45 thousandths, we got the combustion chamber down to 56.8cc. When we angle milled them to 85 thousandths + 15 thousandths flat, we ended up with 51.6 cc combustion chambers.”