Need some help. I'm fairly new to your site. I became the owner of a 1997 WS6 back in August 2007. Well got news today that the engine is shot and will need replacement. While the repair is being done thought this would be a good time to upgrade the factory headers however I live in NJ so I need to pass emissions visual , dyno, the whole nine yards. I saw the pacesetter and mac mid lengths and have done lots of searching on the site. I guess the question is Mac's can come with a catted Y pipe in one of their kits for around $750. I do not see this available for the pacesetters. Is the catted Y-pipe a must. I assume the mid headers won't tie into the factory Y-pipe already there. I see there's an Edlebrock version that is 50 state legal and are shorty headers therefore only the headers would need to be replaced and not require another Y pipe. They are substantial more money and i'm sure any performance gain will be limited. The car is only drive in good weather never really at the track. Just wanted to upgrade now that the opportunity is there. Hopefully you can help a new guy out with clarification as all of these headers claim to be 50 state legal...I need the car inspected in July and do not want a surprise.

Thanks

 

You are going to need a catted y pipe.

 

You need to be looking only at CARB-approved "dual-cat" headers for the 96/97 LT1.

Since you have a dual-cat 97, they have to be "dual-cat" headers, and the Y-pipe can not relocate the cats from their stock factory position. That means the driver's side cat has to be bolted directly to the driver's side header, at the bottom of the header. As a result, the header for the driver's side will usually run upwards from the head ports, above/along side the valve covers, and then turn down to the flange for the driver's side cat is in the stock location.

The passenger side isn't as big a problem, because the passenger side cat is way down under the passnger seat floorboard hump.

That is the strict interpretation of Federal emissions laws. NJ enforces Federal requirements, but the question is.... as part of the inspection process, have they even popped the hood on your car to look at the engine? Generally, on the OBD-II cars, if you don't have an SES light, all they do is hook their system up to the PCM's ALDL port, and check for codes. No codes, systems "ready", and you pass.

Even if they did pop the hood and look, the question is, would they notice if the cats had been relocated? They could probably tell if it still has the required two cats, but what are the chances they would know the exact stock locations on every car they look at? The headers would need to have a welded-on tag bearing the name of the manufacturer and the CARB emissions exemption number, in case they looked at them.

Another thought.... the CARB-approved dual-cat headers are not flow efficient. They will probably flow a bit better than the stock manifolds, but the tortuous path of the driver's side primaries limits the gains. What some people have done is to find a set of the extrude-honed stock manifolds that SLP was supposedly putting on the LT4 SS's. A friend of mine tried the AS&M dual-cat headers, and they melted everything in the engine compartment (AS&M no longer sells them). He ditched the AS&M's and contacted someone he knew at SLP in Toms River to get a set of the extrude-honed manifolds.

Just wait a couple more years, when NJ adopts the CA emissions standards. It's going to get even tougher. I no longer drive my Formula on the street in NJ..... its just too much hassle.

 

I wound up buying the pacesetter mid headers. I called the tech line and he claimed the driver side header will bolt directly to the cat on the driver's side with no modifications. Also the headers carry a CARB number. I called MAC performance as well. They carry a catted Y pipe and headers however there is no CARB number for their set up. So I went with the pacesetter headers and hopefully what the tech told me is correct and they will bolt right up to the existing setup once the stock manifolds are removed.

Thanks for all your help.