My son Jake bought a 72 GS, 350-4, 4speed, stock. He's modded the engine with: Comp Cam duration 212, lift .2933 Headers 1 & 5/8" tubes At this point the 350 was still giving vacuum readings of 17-20 inches, depending on the day weather, idle mixture, primary jets. Running very strong, giving the scary feeling at WOT that "hey, it's time to let off the gas now!!" Then he replaced the stock intake manifold with a Poston dual plane, the readings dropped to 12-13. He resealed at least twice, then replaced the manifold with a TA Performance high-rise dual plane, and .060 gaskets. Still the same low readings of 12-13 inches. And, it's never provided that scary adrenaline rush since. I've replaced all the vacuum hoses and fittings, sealed the casting plugs in the bottom of the Q-Jet main body, the throttle plate phillps screws are thread-locked into the main body, and the all the carb and manifold bolts are torqued to specs. As the low readings started immediately when he switched to the high rise manifold, could he have too much manifold for this motor? Steve
