Hey guys.. the other day i was driving my car around and i noticed that it felt like it was bogged way down or something. it revved really slow and had no power at all until i got up to like 5psi of boost, it was also running a little hotter than usual.. maybe like 10-15 degrees more. i popped the hood and looked around and saw that my turbo had separated its self from my manifold a little bit. so i took it all off and re-tightened the bolts, put it back together, and its still doing the same thing.. i checked the timing and its fine, put in a new fuel filter, and made sure my cam gear didnt jump a tooth. my wideband O2 gague is reading consistent with how it normally runs but its just got no power at all.. my other thought is maybe when there was that crack between the turbo and the manifold, some cold air got on and cooked one of my valves??? what do you guys think?

car specs: 1979 262c, engine: B230FT from an '89 740 (k block), garrett water cooled turbo (about 15psi of boost), 3" dp and exhaust, head gasket is about 2 months old.