Intake Manifold

OK i just pulled the pvc to see if it had suction and it did not so i guess the intake leak is out the question. But i was just thinkin about the timeing chain i used, I purchased a chain for a stock 340 is it possible that the timeing chain is advanced 4 degrees which will make my Comp cam 8 degrees advanced. If this is the case would that cause the engine not to idle at 900rpm and also shake? I also notice when i pulled my timeing light to set the timeing the mark was way off and any slight turn of the distributor would stall the engine out. Could the timeing chain be off? Help, please!!!!!!!