Air and Exhaust Question?

Good idea Jeff! Spray some WD-40 around the crab base and the along the intake to head mating surfaces. If the idle goes up, that is where the leak is. Also check the vacuum hoses.

If you find no leaks and the engine, Try removing the air cleaner. with it removed, readjust the idle. If you get good results, use a 14x3 air cleaner. This is a good size to step up to.

You do not need a bigger cam to use headers. You can use the stock cam with headers.
The Summit header and exhaust system is a good deal.