What i have right now is worse than stock exhaust system and i have recently put in gm 350 330 hp and i was wondering if this could cause bogging at low rpm? I have Edelbrock 1 5/8's headers that have been ported out completely and i have a 3" cat and it goes in to a mid pipe, i don’t know what size but its the size that came with a 87 tpi engine and in the middle it was broken so i put a tube "inside" should of put in on the out side i know but anyways i welded it back and i know that restricts it a lot and on the back of that is a muffler that was put on my car just for the guy that had it could sell it, it is a duel output muffler with pipes slightly larger if not the same size of my primary pipes on my headers .
I know this is probably the saddest cat back the world has ever seen and i am probably going to order a random cat back tonight because i got some $$ saved up and was wondering if a crappy cat back can make you bogg really bad at low rpm because i hope getting a new cat back will help me out. and yes i have tried every thing under the sun to try to fix this problem and i am down to this cat back

 

Down-stream restrictions "tend" to reduce high rpm power, not produce bogs. Less restrictive primary systems "tend" to induce low-end lean conditions, leading to bogs.

I think you need to look elsewhere for your bog problem. The inside-the-pipe fix probably isn't that much of a restriction, but it wouldn't hurt to fix it to regain your high end power.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).