Exhaust Size

Does anyone know the exhaust pipe size diameter on the Y pipe from the manifolds for a 1990 K1500 for the 350 engine? Are they 3" OD? The reason I ask is this spring I replaced my 305 for a 350 and I'm now looking to upgrade the exhaust system. The Y pipe and the inlet and outlets on the Cat on mine look to be 2 1/2" OD. When I looked at the different Flowmaster's or Gibson's the choices seem to differ between the 305 and 350 engines for my year and some of the Flowmaster's Cat-backs specifically mention their's are 3" inlets. Some of the systems don't seem to be offered for the 305 in my year but they are for the 350 which leads me to believe there's a difference. If the 350's were 3" then I think I'd rather get the bigger, correct, exhaust system and replace the Y pipe and Cat. Or in the case of the Cat, a straight thru pipe to eliminate it... no sniffers here. Anyone know for sure before I order any? Thanks,

that me get this straight you want to get bigger than 3"? on my 91 I had stock exhaust at the end of the y pipe in had 3" then to the muffer then duel out each pipe was 2 1/4 inside. I would get what flowmaster or gibson has. If you get to big of pipes you are at a loss then to small of pipes you are at a loss again.

I'm not looking to get bigger than stock. I just need to know whether the Y pipe thru to the back of the Cat were the same diameter on a 1990 with a 350 as compared to a 1990 with a 305. My truck still has the original exhaust that came with a 305 but I now have a 350 in it. If I buy a set of Gibson or Flowmaster's for a 1990 with a 350 engine, will they match up to my existing 305 stock Y pipe/Cat? If your 1991 350 had 3" pipe from the header outlet thru to the muffler then they are diffinitely larger then my current stock 305 exhaust. If that's the case then I need a new Y pipe and Cat also. (or a straight pipe to replace the Cat)

have you considered banks power exhaust systems, they are simple to install and very complete, and best of all, they really make a difference in towing as well releasing back pressure effectively, it's like breathing a new life into the engine, just take note some engines do react differently to these mods, but yeah a 3inch does alot of difference, if your going to be doign serious off roading i would go with stainless steel look at borla they are also good, but my choice would still be banks.

http://www.bankspower.com