What power valves do you have in the carb and what vacuum are you running at idle. My guess you are pretty low on vacuum at 650 RPM. I also think that comp cam you have might be on with a 110 degree lobe seperation which will lower vacuum at idle.
Check your vacuum at idle and if and your power valves in the carb and if needed change the power valves so that they aren't dumping fuel at idle. You will likely need to put an 8.5 or 10.5 power valve in it if you don't already have that in the carb presently.
On another note, are you getting that much exhaust in the cab of your car, if so you need to find out where it's coming from and fix that.
Remember too that changing your jets doesn't change your carb size, it just makes the mixture richer of leaner, so you can only go so small or large before you get into problems.