When did Chevy start using double hump heads?
When did Chevy start using double hump heads? Heads with short double-hump casting marks were used in later high-performance SBCs. Most of these heads had accessory bolt holes and were identified with casting numbers ending in 186 or 492. They were used from '68 through '72 on 302 CI Z-28 engines as well as '70 through '72 in LT-1 350 CI Corvette/Z-28 engines. What kind of heads did Chevys have? Combustion chambers were typically 62 to 64cc and provided higher compression ratios. These heads were found on Chevy high-horsepower 302, 327 and 350 CID engines, including the fuel-injected 327s, from...