Faceman89

The Magnaflow CA Compliant cat is what I would use. I had planned on using the non CA Compliant one on my 89 when I had it.

mh96vette

Bless your little heart... There's more of us than you think, we aren't all that lonely. You don't have to drink the Koolaid to love Corvettes man. I hug every tree I come across and I LOVE my 96 more than anything.

jsinga

If the car is in good shape it ma pass without any cat
CA just have the pipes cleaned out
I’d never put a set of new pre cats on a L98 car

iceman2003

Can you expand on Metallic Substrate converter? Thanks

GREGGPENN

Magnaflow, FLowmaster, XFOrce, etc....make metallic substrate "high-flow" cats with fewer cells per inch. Typically, the ones referred to are 200cpi vs factory 400cpi converters. They don't look anything like stock MAIN converters. They are cylindrical and lack heat shields (like the OEM units.

If I were the OP and needed to pass inspection, call your dealer for the 3" Magnaflow with air tube. Make sure it's a 3-way converter. Our stock 89's used preconverters and a main converter. One handled NOx fumes while the other converted carbon monoxide (IIRC). Nowadays, they sell a 3-way that sits in the main cat location -- that will "convert/handle" everything.

That's assuming you don't need to meet visual inspection for the presence of OEM equipment (since the OEM config included pre/main cats for CA and Non-CA cars). BTW..It LOOKS like the CA compliant Magnaflow converter is something like $1200? That sounds about right. LOL

I agree with the OP that the main cat WITH TUBE is the best route. If you really want to dump all the AIR equip AND don't have to meet visual inspecitions, you could consider putting one 3" metallic [3-way] cat in the belly. Chances are it would work as good or better than what you remove.

Caviat: I don't have to pass testing so I can't speak for the viability of each -- in that scenario!!!

mike1111

stock cats are ceramic honeycomb, best stock cat supports 240hp. Metallic Substrate converter are all metal and depending on size and density of cell, they can support up to 800hp per bank. basically, they can flow the same as a straight pipe.