C3 '68 coupe exhaust pipe, Weld or C clamp?

[Glen Ritz]

I'm having my '68 coupe exhaust pipes redone, all rusted out. My question is, do I need to clamp the pipes at the "thru the frame connections" or can I weld them together? I need to change out the clutch and throw-out bearing soon, and I don't know if the pipes have to be disconnected and moved out of the way to do the transmission/clutch service. Any advice is appreciated....Thanks in advance, Glen

PS. Engine is a 327/350 with headers, and a M21 trans

[Joe L.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Glen-----

The exhaust pipes were originally clamped at the junction between the forward and rear exhaust pipes. You need to maintain this "element of originality" for a lot more than the sake of originality. If you weld them at this point, you better hope that you never need to remove the transmission, because the rear pipes DO have to be removed in order to do this. Besides that, you will have a VERY difficult time getting the rear pipes, mufflers, and tail pipes adjusted properly if you lose the ability to slightly rotate the pipes at the crossmember joint.

The muffler-to-exhaust pipe joint was originally welded. However, you cannot achieve similar configuration by welding SERVICE mufflers and exhaust pipes. That's because the original assemblies did not have a bell joint like SERVICE mufflers. However, you can purchase reproduction muffler/rear exhaust pipe assemblies which are manufactured like the originals.

[Steve L.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Joe,
For what it's worth, I seem to remember that my 73 coupe exhaust was one complete unit from the front to the muffler. I was surprised the first time that I had to change the pipes. I don't remember a weld joint at the transmission clamp.

But again, that was 30 yrs ago. BTW, that first set of pipes lasted a long time, not like the replacements. They were double walled as I recall.

Steve L
73 coupe since new

[Joe L.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Steve-----

I've never seen nor am I aware of any 63-82 exhaust system that was welded at the crossmember joint. For one thing, installing such a system in the car, even at the factory, would be impossible to do as a complete unit and I am unaware of any exhaust system welding that was done at the Corvette assembly plant. Secondly, the clamps used at the crossmember exhaust system joint are dual-purpose. They, of course, serve to clamp the front and rear exhaust pipes together. Their second function, however, is to support the exhaust system at this point by clamping it to the "ox yoke" bracket attached to the transmission mount or the crossmember. Without this support, the exhaust pipes would contact the crossmember and rattle. So, one way or another, the clamps have to be there.

[Michael W.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Just to back up Joe's statement, I have a set of low mileage '73 L48 front pipes (early take offs) and they were definitely clamped two piece pipes. I see no signs of them being double walled.

[Steve L.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Sorry, guess my memory is going foggy.

Steve L
73 coupe since new

[John D.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

Joe:

I just picked up a aluminized steel system from Allens in Carlisle. Are you saying the joint about 6 inches before the muffer was welded originally on a 68? The system I just picked up is clamped there. If this is the case, would it be better to install the system, make sure it hangs right, clamp that joint, then take the muffler and rear pipe down and have that joint welded?

What are your thoughts?

John

[Joe L.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

John-----

In the original system, the exhaust pipe was welded to the muffler right at the muffler. What you are referring to is the SERVICE configuration. That's exactly the point that I was trying to make in my previous post. In the SERVICE configuration, the muffler has a curved extension welded to the inlet side. This curved extension has a bell joint on the end. The exhaust pipe fits into the bell joint and the joint is clamped or welded. However, if welded, it does not simulate the original configuration, at all. The original PRODUCTION configuration did not have the bell joint.

Allen's does have reproduction systems available of the original PRODUCTION configuration. If you wish, I think they would probably exchange it for you. Shipping cost will be expensive since the original configuration includes the welded rear exhaust pipe and muffler assembly. This makes it quite long and UPS oversize. Plus, you'll have to return your existing system which will be UPS oversize, too.

[Jim T.]

Re: C3 '68 coupe exhaust pipe, Weld or C clamp?

On my original owner 68 the exhaust pipe connection clamps also provide an attachment location for two ground straps that was also connected to the frame crossmember.