I will apologize if this is a dupe, but I could not find the information when I looked previously.

I have removed my exhaust manifolds (92 LB9 5.0 TPI without G92) and have measured the outlet to be 2". I have purchased a set of L98 Exhaust manifolds, and they are the same shape and design, yet they measure a 2.25" outlet. I know it sounds like a small difference, but for someone looking for some original looking 'stealth' mods (no headers!!!) I think it is a substantial difference.

Just for further info... my non-G92 car came with a pitiful y-pipe, no cat and a small I-pipe on the cat back. I am installing a 2.5" y-pipe with 3" cat fitting, a high-flow 3" cat and a catback with a 3" y-pipe.

P.S. - I am really starting to have fun with this car.. Finally!!!

website: www.bowtiedreams.com

 

You'll get more from the larger i-pipe than you will from the exhaust manifolds, but the complete system will help. If you're installing a stock y-pipe, you'll get even more if you convert it from a "t-pipe" where the left and right exhaust come together, into a true "y-pipe" into the cat.

 

91 305 t5 single cat is what i had and put the stock take off exaust off a 92 350 duel cat and i noticed a huge increace in performance for an afternoons worth of time. So its the same thing your doing and for cheap its alot better. Keep in mind the pass side exits at a differant angle so the stock y pipe will not work, not that your going to use it.

i have the stock complet running when pulled nothig wrong with it 92 5.7 tpi w 49k and 700r4 w ecm im looking to get rid of if interested