darrlee

Is the stock intermediate pipe on the 85 305 TPI 2.5 inch or 3 inch?

I already have a flowmaster installed by PO. The current intermediate pipe is hand made from some shabby mufler shop and is cracked going over the axle (looks like they used cheap pipe and bad bending work).

I have a local shop that will install a new factory replacement intermediate pipe that is pre-bent for my application for $175 parts and labor installed to my current flowmaster and tailpipes.

I am most likely going to remove the cat as I do not have emissions testing now that the car is 25+ years old.

I am running stock motor, no upgrades.

Is is worth the extra money to buy a "cat-back" system in place of fixing what I have, It seems like I would not gain much HP with the stock set up, remember I already have an aftermarket muffler....

watajob

iTrader: (29)

http://info.rockauto.com/Walker/Deta...?112-11614.jpg

darrlee

Cool, Thanks! I tought the stock Intermediate pipe was 2.5"

SCCAjunkie

I'd go with a 3" cat-back, since yours is 2.5". Also, be prepared for the fact that the shop may not want to remove your converter, since that would technically be a violation of federal law, even if your state doesn't require it anymore.

Oh, and that stock replacement pipe is aluminized, though in Texas that may not be as big of a deal. Around here they last about 3-4 years...

darrlee

Yea but is the 3" really worth the money on a stock 305 tpi with no mods? I found the stock 2.5" intermediate pipe at a shop that has the mandrel bends that they will install for $100 (even better deal than the other shop). The pipe is made by IMCO Performance.

And the cat mod will not be a problem for me to get done, wether this shop does it or not.

I'm thinking with the cat removal and the flowmaster that is already on the car, it should be plenty of free breathing for the stock set up. This is just a "weekend cruiser".

SCCAjunkie

Personally, I'd say it is worth it, but that's just me

I'm sure the 2.5" will be fine for your car though. I was merely suggesting that an aftermarket system might be of better quality that the "OE replacement". If it's 2.5" with mandrel bends, then I'd go for it.

I saw "pre-bent factory replacement" and shuddered. It sounds like you have a decent shop to work with, so if that price is for quality work, it sounds like a winner

paul_huryk

Absolutely! Every 305 (carb, TBI, or TPI) needs a 3" exhaust to breathe right and get maximum HP, not to mention large exhaust restrictions also cost MPG.