Another thing to consider is the later model (like 86 and up?) factory manifolds, which are header-like, but still have all the advantages of a stock manifold.
This is what i run (minus the A.I.R. line which i've removed):
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The v-8 manifolds are also going in the direction of header-like. (85 and up Corvettes, 86/87 and later trucks)
i've run headers on the street and prefer manifolds for a number of reasons, the main is noise, but also heat and leakage......