The original EFI system (not sure about the carbies) had 2 cats. This pipe replaces 1 of them. You will need a second (preferably high flow) cat.

 

My question is this.....I have an 88 f150 with the 300 and it has EFI there is a pipe hooked to a hose I cant remember right now but I think the hose goes into the air pump but what I want to know is does the walker pipe have a place for this? or do I need to do some jimmy rigging and put a place in for it and does it matter if its in front or behind the cat?

 

I think that pipe your talking about is part of the thermactor system(think thats what its called), and injects air into the Cats. If you get down under your truck, you should see it connected to the upper, forward section of each Cat. By keeping the last Cat, you would only need to plug the hole were the second cat was connected to it, and would still have a functioning Thermactor system.

 

Ok thanks1 So if I am going to install the walker pipe and a high flow cat and then a gibson cat back system, should I put the thermactor pipe before or after the cat or does it matter?

 

The stock converter should have a bung for it to hook into it, but a free flower might not have one. If you are going to keep it functional, it needs to go in before the Cat. The extra O2 is either part of the reaction or helps cool it(don't remeber off the top of my head). Anyways, does no good to inject air after the Cat. Good luck.

 

Thanks for the info!

 

Is there any performance advantage with the Walker Y over the stock pipe?

 

2.5" pipe, so it would breathe better. Supposedly the best exhaust breathing is with a set of EFI manifolds, the Walker Y-pipe, and comparable 2.5" or so muffler/tailpipe.If your 300 is still stock with the log-type exhaust manifold, the Walker pipe won't bolt up - it's an all or nothing sort of thing.