Cat Problems

[24c3]

I got my silverado off my brother in a trade. I went to get it inspected today and failed due to not having any CATS. Its got some flowtech headers (no O2 sensor) true duals with flowmaster 40's. THe O2 sensor plug was welded up. I need to put cats on it to pass inspection and put an O2 sensor to get rid of the check engine light. I measured the outside diameter and its 6 3/4 what size Cats do I need 2 1/4 or 2 1/2? ALso do i just get O2 bung and have them weld it on when i get the cats put on? Please let me know what to do......

 

[TruckinAin4Sissies]

If it's the 96+ it'll require 2 cat's. I suggest http://performance-curve.com/thunderbolt-spincat.aspx and at $36.95 (a piece) it can't be beat.

A common misconception with catalytic converters is that "high flow" is different than the others. Wrong.
I suggested that particular one because it's small in diameter and it's obvious that it's a cat' when it comes time for a visual.

 

[TruckinAin4Sissies]

BTW you could always do what I did and hollow-out your cat(s) and use Non-Fowlers to trick the ecu into thinking that the system's all good.
Either that or get a BlackBear tune/0411 (ecu swap) with the rear o2's disabled.

 

[24c3]

thanks.... i got a sticker now