Alright before anyone yells at me for not searching, I did. And there have been some many topics its hard to find definate answers. I probably ordering headers tonight from summit. I am ordering parts sum-g9005 and big-11102y which are the summit headers and the Y pipe for third generations to mount to existing exhaust. Other than time, energy, and some tools, do I need any other parts to mount the headers and y-pipe to the existing stock catylotic convertor? Its only 177.45 with ground shipping, so I thought it was pretty good deal. Will I need an oxygen sensor bung installed? If so, how much should a local shop charge for that? I will put a new o2 sensor in, since the other one is probably factory. Thanks for all the help you can give.

 

Make sure you ask a technician (NOT a sales rep), if you need to re-use you're existing heat spacer!!!

Once upon a time, when I ordered my Edelbrock headers through Summit for my ole Trans Am (specifically made for 3rd gen's), they did NOT tell me that I needed to re-use MY heat riser! They didn't supply one.... and they STOPPED making them, their now discontinued (so it was back to the good ole junkyard for me, since I tossed mine after taking it off.....how fun lol)!

If Summit makes a kit for the 3rd generations.... make sure that they don't utilize them in their kit, and if they do..... make sure you maintain you're original (unless they manufactured their system to be a little longer, and it bypasses it)...

Trust me, ask them! It's not like fabricating you're own with a set of shorty headers.... when its made specifically for you're car, then they design it a 'certain' way.....

Just to clarify some more.... when I took off my exhaust manifolds from my 86 TPI IROC, there was a heat spacer (riser) sandwiched between where the manifold ends, and the Y-Pipe begins. Of course, there was no flap door. But it just goes to show how CHEAP GM was/is.... in that they 'couldn't' just make a 'longer' passenger side exhaust manifold, nooo.... they had to re-use a small piece that didn't even belong there!

 

I am not sure what you mean by heat spacer but I have these headers. I have the Flowtechs which are the same as the summit brand just a bit cheaper and mine were coated. These headers do not come with a bolt on style adapter to connect to your existing exhaust. The y-pipe with the kit is 2.5" and your stock set up on a TBI is 2.25. I had to have an expander put on so I could connect it to my 3" cat and cat back. As for o2 hookup yes there is a bung welded into it. However, you will have to drill it out to get your O2 in. They just welded a threaded bung to the side of the collector and did not drill out the center. You will understand what I mean when you see it. These headers are not emmisions leagal so I did the smog pump delete as well. Check out my website and click on exhaust and you will see what they will look like in your car. Oh by the way, the y-pipe is super crappy and I took a dremel to it to open up the t-flange a little. Look into one side of the y-pipe and you will see the hole they drilled into the y-pipe is smaller than the collector tube. I shoved a dremel in there and widened it out a bit. Once again you have to see it to understand. You better get some good quality gaskets for everything or you will have a leak in less than an hour. I used PErcy's dead soft and collector flange gaskets. Good luck.

 

On third generation cars so equipped with the LG4 engine's, GM used a Heat Riser that was located bewteen the exhaust manifold.... and the Y-Pipe. This was to assist in the 'warm-up' process... as there was a vacuum line that ran to (either) the CARB or the Intake.... which kept the flap door closed (heat build-up), then opened when it reached operating temperature.

On the TPI cars (even though they did not need, nor utilize this device), GM still used that small piece, which simply went from the 'Heat Riser', to 'Heat Spacer'. Without it... you won't get a proper seal, and you'll FRY you're starter solenoid. My ole Edelbrock system didn't come with it, and I didn't evben think I needed it, so when I bolted up the Headers and Y-Pipe supplied by Summit..... I fried my starter within 5 hours!

My only intent in mentioning this, is be careful when it is 'specifically' made for the car.... especially if their inexpensive.