Well, I originally wanted to go with a 9000 series Magnaflow hi-flow cat but was unable because its illigal in california. So, instead would going with the 4000 "carb" series of the magnaflow make a difference vs stock? Are they still considered "hi-flow"? Thanks

 

Factory cats are considered highflow, they won't be loud like an aftermarket highflow like a Thunderbolt but it'll still flow extremely well compared to cats from the early 90's and back. The old pancake looking cats, the pellet style, those are bad flowing from the factory. A buddy of mine had one on his 89 Silverado, had that cat and a glasspack welded in the stock exhaust. The glasspack helped but the cat was holding it back. He instead straight piped the cat section, welded in a Dynomax Bullet and put in dual tailpipes. It moved a lot better after that since he used stock 2.75" pipe and 2.25" tails (TBI 350).

But the point is that if your Blazer is 96 or newer, the OBD2 cat will flow very well and not restrict flow, so a cali legal cat will be fine. Or just move since cali sucks for hotrodding anything that's street legal and newer than 72 or so.

 

So in other words save $200 and stick with the stock cat instead of going with the "carb" cat from Magnaflow because it doesn't really make a difference- they are both high flow? For $200 I would think the magnaflow "carb" series would make a difference over stock unless there is something I'm missing . I cant say I like all bs that goes on in cali either, they want to legalize all the stuff that degenerates society while making illegal the stuff that no one else gives a crap about.

 

Yeah I read in another post you have a 96 so it should be just fine, provided you don't have too many miles on it, eventually it will clog and need replacing but you'll know when that happens, it'll bog down and have no power, a lot like a clogged fuel filter if you've ever driven a car or truck when one of those is clogged up.

 

Yeah, I called more then a few exhaust shops and most em say that "high-flow" cats are just a gimmick, and that basically I already have a "high-flow" cat with the stock one that I have already. But, I did find that the California line of magnaflow cats flow the same as the 49 state ones. So, I think i'll save myself $250 parts and labor and just keep the stock.