munsonbw

iTrader: (1)

It appears I have a failed weld or a cracked pipe at the manifold side cat flange. Before I send it off for welding, is it stainless? The flange itself looks pretty rusty for stainless and the cat pipe is a lot more oxidized than the rest of the exhaust.

Thanks,
Ben

aurora40

iTrader: (1)

I believe it's that cheaper/rust-prone stainless that GM uses for exhausts. It won't rust through, but looks like hell. I assume the cat case itself gets so much rustier looking because it gets so hot.

ColeGraham

iTrader: (8)

Manifolds and cats are cast iron...with an aluminum shield on the manis to give the illusion that they arent piles of heavy crap...

DrSpeed

iTrader: (4)

I believe it's 409 stainless. Magnet doesnt quite stick to it.

munsonbw

iTrader: (1)

Do you mean the cat flanges are cast? The cat bodies certainly are not, but the manifolds are cast.

I suspected a cheap grade of stainless as the rust just did not look like mild steel would rusted. Oh well, better than the exhausts of yesteryear that rusted through in a couple of years in the "rust belt".

Thanks for the help,
Ben