I have a stock 92 RS I just bought and have purchased the Catco Part #9118 3" Cat, and the Flowmaster American Thunder Part#17233 #" Cat-Back for it. I need to decide what to do about the y-pipe. Can the stock y-pipe be made to mate up with the 3" Cat??? Or should I put out the extra $200 on the SLP Y-pipe that hooks up the stock manifolds? I am not buying headers for the LO3 so don't talk about headers. Help please, I need to install this ASAP.

 

It can be adapted. 2-1/4" ID pipe expanded to 3" OD, welded in after the stock y-pipe is cut sufficiently.

I haven't checked into it for sure, but the SLP y-pipe is probably not intended for LO3 manifolds.

 

save up your money a little longer and get some headers with y pipe

 

I told you guys, I am not putting on headers on the LO3, I will wait until I drop a 350 in down the road OK? AND YES, SLP makes a Y-pipe that fits LO3 STOCK MANIFOLDS. My question is if anyone has this, how is the performance? Did it bolt right on? So far, through searches I have only found one person to talk about this on his LO3. Hopefully there are more?

 

Save up your money a little longer and get some headers with y pipe then you can swap them over to the 350 later......duh???

 

why worry about the performance of it when your just going to be putting in a 350 with headers later down the road.....? just get the headers now and that way you have them when u do the 350......

 

I've got an SLP-Y on mine. It is a nice piece if you do not want to go with headers right now. You'll wonder what GM was thinking when they used that piece of garbage they put on stock. I paid an exhaust shop 60.00 to put mine on for me. I noticed a difference and it sounds better too. Glad I did it. Just make sure you get the right one for your LO3.

 

I had one on my 86 peanut cammed IROC a long time ago. Not worth the money IMO. I would just hack the existing t-pipe right before t and get a couple of 90 degree bends out of 2 1/4 pipe, a flow Y collector and a section of 3 inch pipe to connect to the cat.

 

Well, you guys might have me convinced to just go with headers in the future. Today, my 3" exhaust is being put on and the guy calls me and says my MAC Stock Replacement Y-pipe won't fit the stock manifolds like the MAC guys told me they WOULD. SO, I had to just have him adapt the stock y-pipe to the 3" Catco and 3" American Thunder System. Now, I have to return the freakin y-pipe to MAC and all. Oh well, I'll just save up for headers like you guys said. I would have gone with the SLP y-pipe but they discontinued it!