my camaro is mostly stock except for an engine swap its now a 350 i took the muffler of of it but kept the stock manifolds cat and pipe on. i like how it sounds but will it hurt the engine?

 

I done the same thing to my 3rd gen only I had resonated tips. I put over 50k on it with no problems

 

With stock manifolds you should have enough back pressure

 

are the manifolds that restrictive?

 

its not that the manifolds are that restrictive (although they dont promote high velocity), everything combined though will provide enough back pressure to keep the engine running strong on the bottom end of the rpm range. a stock motor can run an open y-pipe for as many miles as you want to listen to it, its not going to hurt anything other than your ears and low end power.

 

Oh no, not the "engine needs back-pressure" myth again! If back-pressure is so good to have, then jam a potato up your tailpipe.
Back-pressure in the exhaust is bad to have for getting "performance" out of an engine, plain and simple. How many dragsters have you seen with cat converters and full length exhaust systems? Exactly!!!
Where that "back-pressure is good" myth came about is from some guys having their valves burn after installing headers and a free-flowing exhaust. "Gee, that better flowing exhaust ruined my engine, I guess I didn't have enough back-pressure".
More modern computer controlled engines react differently and can self-compensate to a certain extent for a more open exhaust. So let's take an old school, carbureted engine like mine for example. In stock form from the factory, everything is balanced out between the carburetor flow, intake, and exhaust system. Now take off that restrictive exhaust and put on headers, free flowing mufflers, and bigger pipes. And you might as well put an open air filament on the carburetor as well. What happens is now your engine is able to cram more air through it since it can breathe a lot easier. But a carb can't compensate for the added air flow because it has jets that are set at a certain size. If nothing is done to increase the fuel flow with the air flow (larger carb, larger jets) you have a lean running engine. And lean running engines tend to burn valves.....and the "too-little back-pressure is bad" myth is born.

 

very well put^^^^^^
x2

 

Thank you very much, I didn't have to preach this time, LOL!

You should hear the R-Tards on Jeep Forum, if you say back pressure is a myth, it will be followed with 10 pages of flaming...

 

I ran headers and two straight pipes by the driveshaft and cut it off before the rearend. Over time it melted my drive shaft seal. I noticed the leak before it got bad but make sure your not to close to anything that might melt.