Alright I'm in the process of building a 383, I'm wanting to run 1 3/4 primary headers with 2 1/2" collectors with a y pipe that collects at 3". 3" in/out catalytic converter and have it step up to 4" after the converter all the way back to the muffler that is 4" in and dual 3" out. would this be a good way to run the exhaust? i think it would still be a good scavenging effect for my 383.

 

that is a good setup but i would get 3inch collectors and a 3 in y-pipe and 1 highflow mac cat(if you had to have one) and make that meet right at where your catback meets your y-pipe so you only have to buy one

but if you can ditch the cat then do it

 

thanks for replying yeah thats probably what i'll go with. what about the catco converters i think summit has them for like $47 or something like that