Question, C3 exhaust juding?

[steve wallach]

I am doing a complete restoration of my 68 BB Coupe. The exhaust pipes that were on it, are GM 2 1/2 pipes with the correct bends and flat areas etc. However, the pipes were some what rusty, I had them bead blasted which left behind a pitted or pebbled surface due to the rust. I haven't had much luck finding correct pipes, so I plan on re-using these. They were clamped to the mufflers also.

My questions are, 1. how much, if any, of a deduct would there be for the pipes being somewhat pitted?
2. Should I paint these with manifold type paint to reduce the appearance of the pitting and or to keep the rust from returning. Or should I let them get surface rust which would make the pitting basically not visible.
3. Should the mufflers be welded to these pipes? Or will they have to be clamped since these pipes wont go all the way back to the muffler body.

Thanks for any help with this,

Steve

[Joe L.]

Re: Question, C3 exhaust juding?

Steve-----

I can't answer your judging questions. However, I can tell you that the pipes that are currently on the car are either GM SERVICE replacement pipes or they are original pipes that have been shortened to accomodate the installation of SERVICE mufflers, GM or otherwise. When a SERVICE muffler with forward extension is installed on a Corvette, the original pipe has to be cut short so as to fit into the slip or bell joint on the extension pipe.

The original pipes and mufflers for your application were welded at the muffler. There was no forward muffler extension with bell joint, at all.

Achieving exact original exhaust/muffler configuration is very difficult to do for a Corvette.

[steve wallach]

Re: Question, C3 exhaust judging?

Hi Joe,

Thanks, I beleive these to be GM service replacements, as it appears there is a place for the service mufflers to slip on to these pipes, they don't appear to have been cut.

Thanks Again,

Steve

[Dick W.]

Re: Question, C3 exhaust juding?

Steve, treat the pipes with something like Pre Lube 6 for rust prevention. They will some for a few minutes when first started up but it will help prevent further rust.

Chassis judges like to see the mufflers welded to the pipes. It can be done to where it is not real obviousl.

[steve wallach]

Re: Question, C3 exhaust juding?

Thanks,

I can probably have the mufflers welded where they would normally be clamped.

I can also put some sort of lube on the pipes as this car won't be driven and not started very often. It is also stored inside.

Thanks again,

Steve

[Dick W.]

Re: Question, C3 exhaust juding?

Lube the pipes, store on a sheet of plastic, and run a dehumidifier and it will stay looking like new for a long time

[Joe L.]

Re: Question, C3 exhaust juding?

Steve------

The mufflers can be welded to the rear exhaust pipes at the point where they are clamped. However, you still end up with the "bell joint" configuration which is quite easily discerned as a SERVICE-only configuration. I don't know if there would be fewer points lost by a weld rather than a clamp.

The original configuration had no bell joint-----the rear pipe was welded right at the muffler.

You can purchase reproduction systems which have this aspect of configuration correct. However, the reproduction systems are otherwise not exactly the same as original GM. So, you can "pick your poison".

[steve wallach]

Re: Question, C3 exhaust juding?

Thanks Joe,

Any idea which way would be better? (for Judging) I'm guessing the GM Pipes,
but I don't don't know for sure?

Steve

[Patrick H.]

Re: Question, C3 exhaust juding?

Steve,

There are (for my 72, which is likely similar) 15 total points for the pipes, and 15 for the mufflers. 8 each are originality, 7 condition. I usually lose 4 points each for the originality of my Corvette Central aluminized pipes and mufflers, and then none for condition. So they cost me 8 points. Stainless exhaust tips are a couple more points off, as are incorrect clamps (repros are now available).

For the 8 points the aluminized cost me, I live with it. I've seen some very nice GM replacement pipes on cars when judging, and they will usually result in a minor deduction (2 points) if they are welded together. For 6 points I'll make sure my clock works, avoid rust, and save a lot of money.

Patrick

[Steve Wallach]

Re: Question, C3 exhaust juding?

Thanks for the info Patrick,

Steve