When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Trying to clean my car up a bit and would like to put the original exhaust back on from manifolds to exhaust tips. I am primarily interested in original performance/sound as the end result. I don't see many options for the y-pipe and cats for auto store replacements. Anyone know current exhaust shop prices for something like this? Was the 89 350 TPI AT ever equipped wit single cat? Appreciate any input on this.
Anyone have the exhaust manifold cast numbers for 89 350 TPI cars and crossover info?
Last edited by MrPackstin; 12-13-2022 at 10:14 PM.
87-92 TPI exhaust manifolds are 14094063 and 14094064.
N10 exhaust components can still be found. Used OE on ebay. New, better replacement stuff from Magnaflow through various vendors, such as Hawk's and Summit.
Dyno Don here on TGO makes an N10 exhaust, but for his headers, not manifolds, available through Top-Down Solutions, a TGO vendor.
Stainless Works appears to offer an N10-style dual Y-pipe without cats, if you wanted to go that route, in which case there'd be no need an AIR system.
And for a finishing touch, OE-cut tail pipes are also available. Here's with a Magnaflow muffler, but there are other listings with different brand mufflers. The tail pipes, alone, are available somewhere, too, just can't find them at the moment, but I've seen them listed. A member here recently got them. https://www.ebay.com/itm/201407124815
Depends upon how authentic you want to get and how much you want to spend. Going back to manifolds might not be ideal for your supercharged engine, but they probably would free-up some space under the hood, if that's a goal.
Edit: looks like the Stainless Works catless Y-pipe might be an outdated product. Personally, for manifolds without an AIR system, I really like these, but mild fab work would be required to fit the Y-pipe. https://www.holley.com/products/exha.../parts/8525HKR
Last edited by LAFireboyd; 12-14-2022 at 05:45 AM.
WOW; tremendous thank you for sharing the knowledge. Plan on selling supercharger kit to fund OE parts...hope i don't miss the HP/torque too much. I will end up putting AIR system back too.
Was it just the TPI cars that used the 14094063 and 14094064?
Yes, 4063 and 4064 are as good as 3rdgens got. The 87+ L98-cammed LB9, and the L98 got 4063 and 4064. The L69/early-LB9 got 1199 and 1200, I believe, which are similar.
You might also need a cast iron spacer for the passenger side, needed for the single cat y-pipe. I'm not sure if the dual cat y-pipe used one, but I'm sure somebody will eventually tell us. The best way to get hundreds of redundant replies is to post something that's incorrect lol. But the spacer filled the gap where the butterfly valve was for carb engines.
12-13-2022, 09:42 PM
