M-1 Intake Manifold
I ran a m1 single plane on the street with the hot 340 509 purple shaft and modified TQ over 10 years it was a killer manifold and combined with 391 rear end it didn't seem to lack for anything. I now run a six pack now but I keep my m1 on the shelf so if I ever go back to a single 4 setup just use a adapter some are only a piece of 16 gauge steel.