Does a High Flow Cat. Converter add hp??

I just recently made a purchase of a magnaflow exhaust for my 98 Trans AM..Also with the purchase i have a decision on getting a magnaflow universal high flow cat. converter, k/N air filter, or indiom spark plugs for free.

Not exactly sure what to go for..i was curious if the converter added any power??

also my next mod is going to be a lid with a k/n air filter.(so either i could get the filter for free or just buy it with the lid)

does anyone have any input on what i should go for???

I think the magnaflow high flow cat converter is in the $70 range if and the filters around $50...if this matters.

thx for your opinions and help

The hi-flow cat will lose you about 5 RWHP over a straight pipe.
A hi-flow cat will gain 3-4 RWHP over the stock cats.

You have two cats. One for each side of the motor. $70 a cat is CHEAP!!


Best spark plugs for the LS1....NGK TR55's.