Has anyone ever had this happen and if so how did you fix it? I’m afraid heating it will cause it to crack once pressure is applied to straighten it out. It’s only off by about 1/8-1/4”. And it came off a running car. 

It's early for obvious but have to ask - have you tried lifting up on the other end?  There's play in those center holes.  Only one stud is visible in your picture.  It should rotate around it.

Put all three in the middle and if it's still off it might be junk.  Or you could grind the opening bigger.  Or use welded beads to pull it down as they shrink.  The metals guys probably know some tricks. 

We had all three middle studs in at one point and couldnt get the holes to line up still. I actually work in a metal fab shop, thats what adds to my concerns about heating it back up. I spoke with a few of the guys in the shop also and none of them knew of any tricks. I am hoping someone here does. My last resort thought was to grind the manifold down a little, grind down the thermostat housing to get some clearance and then drill out the bolt hole. But i would prefer not to do that.

Welders, take a look here.

I'm not a welding expert but I think that exhaust manifolds are difficult to weld because the carbon content changes after a billion heat cycles.

Found a good video though.  I do know that you can use welding to bend things.  I'd probably just find a good welder and ask him to weld some beads on the underside and it will pull that end down as it shrinks.  Then have the mating surface ground flat.

Really though, if you have a local speed shop there's probably an old-timer there that knows exactly what to do.  Or one of the tuner shops, the turbo guys probably warp them all the time.  Warped manifolds are common.

 

 

24 minutes ago, startt21 said:

We had all three middle studs in at one point and couldnt get the holes to line up still. I actually work in a metal fab shop, thats what adds to my concerns about heating it back up. I spoke with a few of the guys in the shop also and none of them knew of any tricks. I am hoping someone here does. My last resort thought was to grind the manifold down a little, grind down the thermostat housing to get some clearance and then drill out the bolt hole. But i would prefer not to do that.

If it won't flex enough, then that is exactly what I would do. Welding is probably a non starter and heat may or may not work

The ports need to match though.  That's the reason it needs to be bent/manipulated back to shape.

It will help if they match for sure but its forced induction so it should be less detrimental than NA. You could also adjust the port match on the inside of the exhaust as material will allow