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i have a 89 RS 305 camaro and i was wondering how much restriction exists in just using my stock exhuast manifolds? headers are very expensive and i think they can be a hassle to install and fit properly having everything else in place, like the nessary AIR tubes, air conditioning, ect. i want everything to fit as originally equiped, however i need to have a better cat and cat back. i was looking at summitracing.com and i noticed i can get a catco CTO-4115 higher flowing cat. it has a 2-1/4" inlet and a 2-1/2" outlet priced @$105.69. a flowmaster catback part #flo-17234 is also avaible. its is a 3" catback system that tappers down to 2-1/2" at the cat attachment point priced @ $339.95. so using this setup it would go from a 2-1/4" Ypipe to the cat. the cat would also act as an adaptor 2-1/4" to 2-1/2", and the 3" exuast is designed to mate up to 2-1/2". how much performance gain would i see vs. going with full headers and Ypipe 3", the entire system. the cost would be 450 bucks for the entire setup and it would without a doubt sound alot nicer than stock, and should ad some power to the cat. a full 3" system from the block back would likely the same prices already listed plus coated headers 500 bucks and Ypipe. it would cost almost twice as much. if i could see an aceptable gain by going the way if suggested, i would be able to spend 500 bucks towards something else my car will surely need. im on a limited budget and want to get the most bang for the buck. if im not going to see a significant gain by buying headers with a stock engine, its a waste of time and money for me. my Ypipe is also almost like new and the manifolds are also in good condition, so why replaced something that still has alot of life left? any thoughts?

Pat Hall

iTrader: (31)

I own the exact same car as you, 89 RS w/305 TBI. While you may not necessarily want or need to upgrade to headers, I can tell you without a doubt that if you upgrade to the 350 TPI exhaust manifolds with the larger y-pipe and 3" cat, along with a 3" catback system from Edelbrock or Hooker, you'll notice a big difference. Even with the 305 TBI, the 2 1/4" exhaust system is pathetic and way inadequate. I put the above mentioned stuff on mine and couldn't believe the difference, not only in power, but sound too! If you put an ad on the classifieds here, you should be able to pick up the manifolds and y-pipe dirt cheap from anyone with a TPI car that ditched their stock stuff for headers. I ran the Edelbrock 3" single cat catback system with mine. The catback system will set you back about $250 from Summit or Jegs. The Hooker catback is a little cheaper and works great too. My car actually sounds more like a healthy 350 now instead of an anemic 305. Just make sure you get both the manifolds and the y-pipe. The larger y-pipe won't fit the smaller manifolds. Ask me how I know. Lol. I ended up hollowing out the old 3" cat I got with the TPI stuff and welding a straight pipe through the middle, but if you want to go with a brand new, legal cat, buy the Catco 9118 direct-fit cat. It works perfect with this setup. You won't be disappointed if you go this route. You'll retain the durability and ease of factory manifolds, and your performance will definitely improve over what you have right now. I've got a set of coated Hooker 2055's going on mine this spring, but I've been quite happy with what's on there right now. If you have any other questions about doing this swap, feel free to send me a PM.