stumble/hesitation

Ill look up the weak accelerator pump (although it is a brand new carb), i do have vacuum hooked to the dizzy, power brakes and climate controls. if I find a leak, should the idle drop (less air for the air/ fuel mix), or is there any other indications that there was a leak? I havnt had the plugs out since the new carb and MSD, they were fouled before that but it was running like garbage, far better since the new msd and carb. Checking the plugs and compression check, think theres a bad cylinder? shouldnt there be smoke from the exhaust if a cylinder is bad? Maybe not if its a valve?