So I just got 737 back after the kelford 272 cams, supertech springs, AEM cam gears install. They had the belt(newbelt but no name brand, old tensioner)let go as they started out of the shop and I get a call about a slipped belt bad tensioner blah blah blah. Well they offer new valves and give me the cometic head gasket, greddy belt and OEM tensioner at cost and knock a couple hours off labor. I brought it home running but man it vibrates at cruise speed like crazy and makes a weird metal rattle between 2900-3150 rpm, then it clears out but the vibration gets worse as you climb rpm. I haven't boosted the car past a couple pounds and haven't rev d it past 4100 since I'm really concerned. I plan to take it to 3sx next week and let them look at it but ANY helpful advice or guidance would be Very much appreciated. What the hell could cause that rattle and is the vibration just the nature of the big cams? It actually has a decent bottom end grunt but t did before. 3sx will be installing my injectors and dsmlink next week so guess that will help data wise but I am so disappointed. The car ran great smooth and easy, now not so much. I can tell even the little bit I've ran it is a whole different beast, I really want to open it up with a good tune but I'm terrified it has something wrong.