I installed Hedman 68460 longtubes. They went in extremely easy from the bottom. But they do touch in a couple places. Ive seen several posts on using a hammer to dent headers to not touch, does this cause any negative side effects? I wouldnt think a couple small dents would hurt but Im not sure. Any thoughts?

 

My header never fitted good, idk why. I always like to grind on A-arm mount or k member a little....why hurt performance...

 

i dented mine where they hit the k-member on the drivers side and saw no negative effects, car dyno'd 300rwhp/355rwtq

 

I notched my k-member where the tubes would hit.
You'll have clearance issues with or with out poly mounts too.

 

I decided just to use a hammer on the headers. It only took 2 small dents between the both of them. If they would have been a more expensive set of headers and I would have done something similar to what you did.