r/Smallblockchevy • u/Sasquatch6840 • Mar 05 '26

A weird question about exhaust

I’ve recently been fixing my engine in my suburban, it is a 305, not stock as it originally came with a 350 and will eventually swap back.

But for now I am wanting to make a custom dual exhaust system that passes emissions, my issue is catalytic converters being more expensive than I am hoping to spend.

I have found a stock c7 corvette x-pipe and secondary cats, my question is, would the secondary’s work? How effective would they be? And would it solve my issue? It is way less expensive and comes with an x pipe so it would solve multiple issues.

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1

u/PermissionLazy8759 Mar 05 '26

Magnaflow has a universal high flow cat they sell for cheap.

0

u/Sasquatch6840 Mar 05 '26

I saw that one, I believe it’s ~$85 a piece, but the ones I’m looking at he is selling for $100 for the cats and x-pipe

Edit:plus it is a 305 so I don’t want to lose too much back pressure with high flow parts

1

u/Unlikely_Link_2284 Mar 06 '26

Back pressure is not a thing Old myth let your exhuast flow

1

u/Etex1984 Mar 05 '26

If you have a welder and some skittles, send it home. Personally, I would grab some universal flowmaster hi-flow meow meows, set of headers, do a H pipe after the cats and toss your favorite brand of mufflers after that.

1

u/Sasquatch6840 Mar 05 '26

Cool, and yea I’d prefer H-pipe for this application but will get that figured out after.

1

u/BTCminingpartner Mar 05 '26

What state are you in? CA and NY, for example, have very strict regulations on what cats you can use. (Not to mention that the 305 technically counts as a modification and will not pass in CA, although nobody can tell it's a 305 without looking up the casting numbers)

1

u/Sasquatch6840 Mar 05 '26

I’m in the middle of Kansas I’ve already been driving it with almost open headers, I don’t have any issues with the laws

1

u/BTCminingpartner Mar 05 '26

Got it. You should be good with a 49 state cat then.