480602 Manifolds
 

Have some leaking headman headers that are a complete pain to work around, looking to go back to a stock style manifold. A guy local has a set of 480602 D port manifolds.

Car is a 1968 GTO, Engine has 62 heads and is bored over 0.030" with a mild cam and crappy pistons. Looking to upgrade the internals at some point in the next couple years, but nothing over the top.

What should I expect to pay for a set of these manifolds, and anything particular to look at? Should I hold off to find some 6 bolt manifolds, or are the 4 bolt manifolds sufficient?