well one of my buddies has a 90's 540 turbo wagon and he got a new turbo and manifold...well we put the engine back together and fired it up and theres this aweful NOISE! ! ! a loud as knock! like super loud...the turbo still spools up so i don't think its the turbo? ? any input on this?

 

so you only took the mani and turbo out right? check all your bolts again

 

Honestly there's not enough info. Most likely cause would be you left something where it shouldn't be. I assume there were no bad noises before? How long did the job take? Could have just thoroughly drained the engine of its oil haha. Unlikely but a possibility. We are basically shooting in the dark on this though.