Ok, so I went to hook up my exhaust to my headers after I finished everything up on my trans project. Well the passenger side header collector is now sitting about 3/4 of an inch higher than the driver sied. I thought maybe the trans crossmember was on wrong somehow even though I dont know how you could even put a th350 crossmember on wrong on our cars. Well of course that wasn't the issue so I started looking at the car and how it was sitting on the jack stands and stuff well the chassis was twisted a little bit since everything wasn't even, so I thought that may have been the issue. Well it helped a little bit and allowed me to at least get the bolts through the holes but at that point the h-pipe is in constant contact with the trans crossmember. So the only thing I can think of is some how while the header was off the car it warped or something. Its a really weird situation and the only thing I can think of to fix it is to heat up a couple of the bends with a torch and pull it down or get a new set if that doesn't work. I will get some pics up in a minute.

 

Here's some pics of each collector! The pic on the left is the passenger side and the one on the right is the driver side.

 

Just a shot in the dark but try loosening the header bolts at the head, and see if that helps. You may have to take it off the jack stands for that to help if the car is twisted while on the stands.

 

^ I was going to suggest the exact same thing. Having the headers rocked even just a little bit at the heads, means quite a bit of up or down movement down at the collector.

 

Ditto! I had a similar issue when I pulled my big block out for rebuild in 1999. When it went back in the headers didn't mate up to the exhaust system well. Loosened all the header bolts, then bolted up the collectors, and then retightened the header flanges to the block. All was fine after that.

 

I actually already had the header bolts loosened up at the manifold and took it off the jack stands. Its kinda got me baffled a little bit!

 

I may go and play with the mount and crossmember!