I have a mildy modded 350 TPI, (SLP runners, ZZ4 Cam) with hedman shorties and 2.5" y pipe. There is no cat, and a 3" hooker cat back.

Am I going to see a difference worth the $40 to change the y pipe from 2.5" to 3"?

Thanks,

Matt

Are you talking about both pipes being 3" or both pipes being 2.5" and joining to become 3"? The latter is the better setup for a street car. Dual 3" pipes is way too big for a 300+ HP engine.

as it is now it is two pipes that come from the collector and y into a 2.5 and then dump into my 3" catback. Im wondering if itll be worth $40 to convert the ypipe to be 3".

Ok, yes it is worth it to have the outlet of the y-pipe be 3". Think about it. Four cylinders each flowing into 2.5" then merging to eight cylinders flowing thru a 2.5" outlet. You know that has to be restrictive.