I have an '87 Z28 with LB9(305 TPI). I was wondering, what size is my stock exhaust? Isn't it like 2 3/4 inch? Or is it 2 1/2? I'm thinking about experimenting with some stuff... anyone?

 

I thought it was 2.25??

 

Stock is 2 1/4!?!?!?! Good gawd that's small...

 

I'm not positive though...

 

2.25" is for 305 TBI.
2.50" should be 305 TPI
2.75" should be 350 TPI. I wouldn't be surprised if some 305 TPIs got it though.

go get a tape measure and measure the circumferance. C=2 * pi * d

circumferance equals 2 times pi times the diameter.

d = C/(2*pi)

 

Thanks Tas. I'm gonna prolly replace my cat with a piece of pipe and throw on a glasspack for now. No tips to deal with when it gets paint&body done. Anyone know what half decent brands are? I don't want something that's gonna blow out easily... or do they all blow out easily? That one on the sounds page is pretty awesome...

 

glass packs are for trucks and they sound really horrible while the engine is under load. unless you want your car to rap out like a farm truck dont get them. get a good muffler like hooker or flowmaster.

 

primer84z: I have and 80 series flowmaster on it right now and it sounds like total @$$. Have you even heard the clip on the sounds page of an '89 IROC with glasspack? It sounds at least 5 times better than the blowmaster on my car right now....

 

87 is one of those grey years where it could be anything. You best bet is to measure it like Tas said. He's right for the most part. I know the 89-92 305 5-speeds with dual cats got the 2 3/4" pipe, because my car had one. The ones with a single cat got the 2 1/4" pipe. And yes its too small.