Put your hands on a 15622 Walker converter or an old OE take-off

 

Unfortunately for me I can't get an old one very easily. Salvage yards in PA aren't allowed to sell them. So they all get scrapped before a car gets put in the yard. For the 82-85 four bolt flange it's easier. I can just order a gasket and turn that into a .DWG file. So for the 86-91 I might just have to buy a cat and then sell it after I get the measurements.

 

describe what u need exactly. i have both strapped to the ceiling in my shop

 

Do you have an old cat from a 86-91 non ZR1 laying around that you would be willing to sell?

Either that or if you could take some measurements that would be great. Pipe diameter, overall length, spacing of the two bolt holes and the size of those holes.

 

I literally have my exhaust standing right next to me, off of my '84...stock converter (40K actual miles), I'm no computer guy, but I could get you very accurate measurements and an accurate tracing of the flange perimeter as well as pics...just thought I'd offer! I believe if a guy got a batch of flanges cut by a local water-jet and sourced some oval pipe, setup a jig...you could hammer them out pretty quickly!!! Sorry I can't offer any help with the '86+...Let me know if you decide to get 100% serious about it and if you want I'll send pics and measurements through the forum and could mail you the physical tracings, if going that route would help!!!👍
edit: the picture that typical boomer provided, I believe is what you would want the finished product to be like....very nice piece!

 

https://www.ebay.com/itm/37374221198...4dead5582ff4a2
Found gaskets on E bay.

 

I had ordered a new y pipe from Speedway that shipped a DynoMax y pipe that included a cat delete pipe. DynoMax might make one for you. I think it was like $240 shipped for the y-pipe and cat delete pipe.

 

Thank you, you're awesome. On the 82-85 version I really just need the overall length. I know what it's supposed to be but if you could grab a tape measure and tell me for sure what you's is that would amazing.

I ordered one. As soon as it comes in I'll order some oval tubing and send my doodle of the gasket to get the flanges cut on a laser. Water jet is way more money and for exhaust parts the laser should be good enough.

 

Hope these pics help.

 

Yes it does, thank you.

 

Slightly off topic, but I was actually making a set of test pipes this evening. One finished so far anyway.

 

^^^^^^^^^^^^^ Interesting project

 

That's not off topic. This is a thread about test pipes. I feel I hijacked this thread by talking about selling them lol.

Anyway I'm very jealous of your fixture table. Getting one is on my bucket list.

 

https://amzn.to/42NGRIK

That's the one I have. Just bolted a big chunk of aluminum heat sink to it to reduce warpage.

 

Finished up last night.




Exhaust system now finished except for brackets to hang and support. Needed test pipes for initial startup with all the assembly lube, and possible unburned fuel before a base idle tune and setup with timing light... that could foul up the cats. Test pipe useful later perhaps, but got some high flow 100cel cats for most of the time as it will soften the loudness, make the fumes more pleasant, and help with any roadside visual inspections and interrogations when driving on the street.

Here’s the rest of the exhaust with Helmholtz tubes that may be modified for length in the future, idea is zero pressure loss but noise attenuation at an annoying drone frequency. It also forms a nice upper diffuser.

 

Your exhaust looks great. I'm wondering about the "roadside visual inspections and interrogations" part though? Do the cops where you live really do this? That sounds awful.

 

Maybe that's a little bit of an exaggeration here, but California next state over, it's like that for sure, so there's risk. At least having cats can get you off the hook. You get pulled over for any window tint for example, and then the inquisition about non-OEM components start. I've been there a lot thoughout the years, only twice did they ask questions, being polite and saying the emissions are much cleaner than OEM standards gets me off the hook, but it's always a risk of getting impounded or ticketed. My truck could be impounded if a smart trooper asked the right questions. I'm in Arizona, and it's not very common, but we do have emissions inspections and testing in most urban areas. I can get just about any car that runs on all cylinders to pass though, years ago I'd cruise the classifieds for cars for sale cheap because it wouldn't pass inspection.

Years ago, I drove an old van, and filled it up with Avgas (because it was free, from defueling an aircraft prior to an inspection). Drove it through a small town in AZ called St David, and got pulled over because they could smell my exhaust fumes as I drove by, haha... 100LL has a little bit of a fragrance. I did get the the list of questions about emissions equipment being removed. Older van didn't have cats, I think it just had a single cherry bomb muffler. No ticket though.

 

Yeah, if your car is obnoxious, the cops will pull you over for that for sure. But it isn't the CHP doing it; usually it is small city police departments. Carlsbad, CA has some of the worst cops when it comes to this. But, if you don't hoon around acting a fool and your car isn't slammed to the ground with weird lights under it, you can usually get away with whatever here and avoid those roadside inspections.

 

Here in PA you would get a ticket for doing something stupid on a public road like doing a burnout or speeding. If the car had a real loud exhaust and you were inside a borough that would also get you a ticket. But the cops here have never looked under the hood any time I've been pulled over. They leave it up to the inspection mechanics to decide if it's road legal. If it has a sticker on the windshield or classic/antique plates then they don't care.

I feel sorry for you guys. I didn't know it was that bad.

 

It really is punitive and stupid. Reckless driving makes sense to police. But the other stuff...meh.