Thank you very much to all for the input. I was able to remove all the bolts yesterday based on your feedback. I just wanted to make sure that I was not damaging anything when I initially started the removal process. I'm not sure at this point if I will install headers or stock exhaust manifolds on the 340 engine that I plan to install. However, if I do consider going with headers I will be looking at the bolt position relative to the tubing. Sounds like TTI headers may be the way to go.

Happy New Year and thanks again!

Vinny