SOLVED! 318 2500-3000 rpm idling issue. Don't think its a regular vacuum leak. Swapped 2 intakes, 2 carbs ,and 6 different gaskets still no luck.

George,
It is NOOOOT ign timing. Or anything to do with ign. If you set ign timing to the generic 8-12* BTDC, the engine will idle at 500-1200 rpm, depending on the cam. If the operator is smart & increases idle timing, such as using man connected vac adv [ or some other method ], idle rpm will increase up to 300 rpm higher. But rpm will never increase up to 2500 rpm just from timing alone.....