TripleBlackZ06

Does anyone know of a company that makes high flow cats the stock exhaust on a c5z ?

Vetteman Jack

I believe Random Technologies makes them - you cut the old ones out and weld the new ones in. Not sure if you have to do anything else though. Someone else that may have switched to them can answer that.

grantv

Are you looking for the OEM or a replacement? Replacement I used MagnaFlow.

Gordy M

Basically the stock oem cats are hi flow type, it was the early 70-80's cats that were more restrictive.

Dirty Dog

This is so true. The cats back in 'the day' were crap, and horribly restrictive. Today, they're really pretty good.
I'd say if your car is stock, there's no real reason not to use OEM replacements. On the other hand, if you're putting on headers and all the rest, it's worth the cost of upgrading the cats, too. I used Random Technologies cats. They do flow a little better, and on a modified car, the little things add up.

grantv

Good point. I assume his cats were removed, or are no good. One of mine was discolored at 45K when I was installing headers, so I dropped MagnaFlow units in.
OP, why are you wanting to replace them?

TripleBlackZ06

Thanks I was looking increase the hp with mods & a tune all while sticking with the original exhaust to keep the dd drivability

TripleBlackZ06

Thanks vetteman I looked into them & seems they went out of business

grantv

Removing cats entirely gain is about 5HP? If your factory cats are healthy the gain would be minimal I'm thinking.

Greg_E

You can also try Kooks or LG for the high flow metal matrix converters. Not sure if they list them separately on their websites but they use them on their exhaust systems.

leadfoot4

Maybe this is why.....

Dirty Dog

I've seen a few tests that showed a power LOSS when going catless.

TripleBlackZ06

So it seems like the general consensus says to leave them be so that is what I'll do , thanks for all the feedback everyone...