(I finished this a week ago but haven’t had time to write anything about it until now.)
For three main reasons, I took the exhaust center sections (from headers to mufflers) off the Chevelle to replace the clamps with welds. Being that this exhaust was originally assembled in a storage unit years ago as a means to get the car back on the road (since the factory tailpipe had fallen off and was filling the cabin with exhaust) it was clamped, and I kept with the clamps to tweak it when I swapped in the 4 speed (which required different headers).
The first reason for the weld-to-clamp-conversion is visible above - which would you rather have? The welds are the right way to do it and look much better.
The second reason is that the clamps were, as clamps often do, leaking a bit.
The third issue is that on one side I had a major clearance issue between the ball flange and the crossmember, as that side’s collector sits a bit higher because of course it does. Clamps and slip fits require the pipes to be straight, but when welding the same you can sneak in a bit of an angle. I also used the opportunity to move the ball flange forward a bit and take the difference out of the header-to-ball-flange section for added clearance.
Once welded up (yes, some of it is stainless, some is mild steel, you can weld it all with mild steel mig wire but it’s not the “correct” way to do it) I put some silver header paint over the welds to slow down their inevitable rusting and put it all back together.
It works, sounds the same out the back, and doesn’t leak, though I’ve only driven it up and down the driveway a couple times since I’ve been busy and was out of town for work most of last week.
As an aside, yes the welds look like shit but, not only am I not a welder, they’re on dirty metal of varying thicknesses and coatings which the wire wheel may or may not have removed. I think they turned out okay.
For those curious, the back end of these pipes slip fit into the mufflers and are secured with band clamps.