my setup is a 383 lt1, mid tube headers, true dual 2.5 pipes into 2 dynomax 12" bullets. this is in my 89 chevy c1500, and the exhaust is dumped right after the bullets, before my axle.

i have emissions that i overdue, so cats need to be installed i was thinking some high flow cats from summit would quiet it down enough and give me a little more backpressure, since there is close to none there now. lol. will these cat's really affect my performance? should i have the exhaust shop install them with flanges so i can unbolt them later on? what have you guys done for emissions.?

 

I just had an exhaust shop weld a pair of cats. into my y-pipe for emissions purposes. A good high flow cat. should result in little to no loss in power.

 

Use the larger body carsounds or equivalent. Don't go with the mini-cats
if you can fit in larger ones. Go with cats with the largest cross section
that will fit. More cross section means less loss at a given flow rate.

 

are you saying you should go with one cat after the Y as opposed to two 3" minicats before the Y? ...as far as flow goes anyway