I ran Hedmen Elites also. I had them on my 350 w/SM465/205 combo. The only mod was to slightly relocate the Z-bar, the frame mount position had to be move toward the firewall about 1". No shackel issues. Nice heder for sure, the 99 dollor type headers are the ones that rust up and leak from the thinner flanges warping.
I found a pic:
See the frame bracket and the new location for the nut. Thoes Hedmens didn't change much in color also.
