i took brake cleaner and did this and couldnt get the motor to stumble or change tone anywhere and while i was replacing all of the vac lines i did check to make sure the check valve is working properly and it was. While i replacing the line that runs under the snout of the s/c i did notice that there was s/c oil on it so i dont know if i should pull everything off again and check the gaskets cuz im thinking the guy the did my new motor didnt put new gaskets on when he took the s/c off my old engine and put it on the new one. The only thing is, i dont see anything else leaking around the s/c besides the little amount of oil leaking from under the snout. The new lines did help though because i was only getting 8 or 9 in Hg for vac before the new lines and now im getting 10 to 12 and if i rev the engine while in park it actually gets more vac... pops up to 12 to 13 when i rev it now and before the new lines it would just drop down to 2 to 4. I dont know if it makes any difference in finding the problem but ive noticed that while im cruising down the road at 60 to 65 my vac is anywhere from 4 to 6 and then if i let off the gas completely it will pop back up to 13 to 14 while i just coast. i dont know if any of this even helps but i dont know to much about this and im just trying to toss things out there in the hopes the it will help someone diagnose what is wrong.