468 ci exhaust question

[67chevy1]

Originally Posted by davepl

What makes a big block manifold a COPO manifold?

COPO Stands for corporate office production order, they were used on the high horsepower chevelles, camaros and maybe a few others. The number casted onto the manifold is how you can tell and they're supposed to flow better than the other production manifolds, but I don't know how much better or anything else. I think headers would look cooler, but it's kind of cool also knowing I have some copo parts on a pickup. They're kind of rare and expensive when you do find them.