First of all im not jumping around i asked what the difference was and now I know the difference. I never said I was gonna run manifold vacuum i just said I understand it now. All I said was I would have to try different things to see what worked best on my engine. I don't understand why yall grown *** men are getting butthurt because i want to learn more way than one and understand the difference between the two! Sorry for wasting your time feel free to ignore me so I don't waste any more of it!