SB EXT. MANIFOLDS QUESTION
Probably the best would be 68-70 340 manifolds but they are very pricey. I'm using Magnum truck manifolds they flow much better than the log type manifolds in other sbs and they are cheap. The ports don't match up well but that's nothing a die grinder can't fix. They come with a 2 1/4" and 2 1/2" outlets depending on the year of the truck.