SSAC's are what dagger linked from ebay. They're selling for the same price as going directly to ssautochrome.com now, so might as well buy direct.
I've installed/uninstalled every style of header over the years for people, and there's a reason that the past 6+ I've done were all SSAC's. When installing, I swap in a ZZP flex, and use Torca AccuSeal clamps with copper RTV, and folks go on their way happy. There is ZERO welding involved if you want to install them as they arrive, though.
For a cat, it would need to be welded in. I did one last month on an '02 Monte SS and here's the line-up before assembly:
The d/p needs to be cut so that the cat begins at the end of the last bend (leave 1-2" of straight on the d/p, since the cat can slide over it). Cut half of the expanded portion off the flange pipe off, right behind the end of the slits, to butt & weld the rear of the cat to that. Some care needs to be taken to keep things aligned, and you may not want to have the cat sit flat, since our tunnels aren't always wide enough to fit them straight.
I've got gobs of SSAC pics in various locations, if someone needs an example.
- Dave
