Thanks to everyone for your timely replies with comments based on your various experiences! That's what is great about this site.
If restoring to original, was it originally welded in the spots you want to do ? . . . I'm with gnicholson in that I would mock up everything first with more things assembled that might have issues with interference. . . . I know we would all like to think that a quality reproduction exhaust such as the ones from Gardner or Waldron would go right on with no issues but whose to say on a slip over fit on a pipe to another pipe exactly how much of the one pipe has to be pushed into the other ?. One might need to be pushed in until it cannot go in any further while another may not need it to be pushed in as far but still in enough for the clamp when tightened clamps both pieces together. Jim
I had been making the assumption that the mufflers that were installed at the factory were welded to both the head pipe and the tail pipe. What I'm hearing now from more than one source is that the muffler was welded to the head pipe but not to the tail pipe. That's good news as it obviously allows for some adjustments for how the tail pipes hang. It appears that a critical measurement will be how far away from the bottom of each quarter panel does the exhaust tip hang? Each side needs to match. If the tail pipe can be "twisted" at the muffler because it's held by a "U" bolt, then each side can be matched.
Basically, everything else that attaches to the frame of my El Camino is in place now. I don't see anything interfering. The fuel tank, a possible interference point, sits behind where the exhaust tips point out so I don't see an issue there.
If it were me and I had to live with the results, I would wait to weld. Sure the factory did things a certain way, but we don't have the benefit of all the drops, sub-assemblies & factory parts to replicate it.
Well . . . welding would be easier now, so I'm trying to take advantage of that.
It would be "more" correct to weld the head pipes to the mufflers as the original exhaust was made with the head pipe and the muffler as a single assembly. . . . The tailpipes are installed conventionally with U bolts at the muffler end and circular clamps over a suspended hanger at the rear. I'd install the body and adjust the tailpipes as needed for clearance, then clamp them down. . . . unless they have changed, the hangers supplied by Gardner are not correct. The "U" bolt is slipped over the pipe with the closed end of the"U" at the bottom, then through the clamp saddle, then through the hanger and the nuts are installed at the top. Gardner's hangers are made so the open end of the "U" faces down.
I am very interested in originality, but at some point I need to draw the line. I'm not up to cutting off the stub at the front of the muffler and butt welding to the head pipe. I'll just weld at the stub. Thanks for the info about the orientation of the "U" bolt. It appears that the system I got from Gardner is correct. Cal asked for some pix of the installation. I'm including those, plus a closeup of how the front hangers I have from Gardner are configured.
Again, all comments and suggestions are appreciated.