Carbon Steel or Aluminized Exhaust?

[Eric F.]

I'm doing a frame off on my 75 convertible and now it's time to install the new exhaust system. The original catalytic converter is in serviceable shape so I'm reusing it. The original pipes look to rough to reuse so I'm going to replace them. I want to Top Flight but we'll drive this car so I also want to be practical.

Corvette Central offers them in carbon steel or aluminized. I'd like to hear what some of you have used or prefer.

Thanks.

[Dick W.]

Re: Carbon Steel or Aluminized Exhaust?

The pipes were originally carbon steel. Aluminized pipes will take a minor point deduction. Be aware that all the replacement pipes available from the vendors differ in pipe configuration (bend shape) and will also warrant a minor deduction for that. Driving your car to a meet will offset quite a few deductions if you live any distance from a meet. Just ask Roy Bratz about driving points

[Mike M.]

Re: Carbon Steel or Aluminized Exhaust?

i use aluminuzed and usually don't take a deduct as i black out the c-1 exh systems.mike

[Mike McKown]

I'm not a points chaser and I dislike rusty pipes

so it's an easy choice for me. Aluminumized.

I'm not too sure I'd trust that converter just because it looks okay. Older ones have been known to stop up. I'm not familiar with how you check it. Maybe somebody will comment.

[Duke W.]

Re: Carbon Steel or Aluminized Exhaust?

The original bead bed catalyst is very heavy and restrictive. A modern monolithic is lighter and offers a lot less restriction. There were only a couple of bolt in converters used for all GM cars in those early catalyst days, and good monolithic replacements can be bought for about $100.

Of course, a modern monolithic type will loose points, but you should consider it after you've completed judging or just swap to the original before your car is judged, which is easy because it bolts in.

Duke

[Stephen W.]

Re: I'm not a points chaser and I dislike rusty pi

I worked in a Cadillac Olds dealership in the 70's and remember they had a tool to vibrate the Cat and make all the little pellets fall out. Funny I don't remember them putting them back in? They also had a "test tube" which was a short "replacement" pipe to fit in place of the converter. This was only a temporary use to test the converter.
So as far as testing the old converters it seems like they just pulled it out to see if that fixed the problem.

[Joe L.]

Re: I'm not a points chaser and I dislike rusty pi

Steve-----

I think that the "catalytic converter test pipe" is now illegal for sale nationwide. The USEPA finally figured out that most of the time they were used, they were left on the car after the "test".

GM used to sell a kit for "refilling" the beads in the bead type converters. Just how often one of these was actually sold, I question. Of course, now, if you have a bead type converter that's "empty", you'll NEVER pass an emissions test if your're required to do that.

[Chas Henderson #28127]

Re: Carbon Steel or Aluminized Exhaust?

I ordered caron steel or my 71 from Corvette Central and I am very happy with them. I have had them on for over five years now and they are in good shape. I put only about 4,000 miles a year. They have judged well. I do lose points for the mufflers - no "w".

Chasman