someone told me the dynomax cat back doesn't work good on the 350 tpis because the mid pipe is only 2.75".any of you muffler exhaust guys wanna give me some info could i maybe leave my 3" pipe on the car and just use the muffler?

 

I use to have that one on my car, 305ci. It is 2.75", i would just keep the 3" you have and go with a better muffler like flowmaster or something.
Matt

 

The Dynomax Ultra-Flow came on my car....never botherd to measure the I pipe.....All I know is that it has an nice idle to it and is quiet on the road at around 1500-2000 rpms but when you open her up it is loud. I like this because the exhaust is not obnoxious uless you want it to be. I am pleased with it. People don't think much standing next to the car unless it goes into WOT.

 

I went with edelbrock thru SLP... true 3 inch, very nice kit, good install... happy camper!