Hello..
What years came with them..?
and Am I correct in thinking the other g.m. a body's part would also work..


Any venders that make them?
I know for my g body many venders make a tube or square tube crossmember to allow duals down both sides..


Thanks

 

1973/1974 and yes, other GM A body cars will have them.

Yes.
https://www.google.com/search?q=1973...on+crossmember

 

^^^^^^^^^^^ thank you..


Sad part was I didn't google.
I went to summit and used the make /model year then looked, figuring it narrow the parts listings down from 100's to the ones that would fit and got zero.


Same thing as I looked for a diff for the car.. the listings blank, backed out of the 75/olds/cutlass and went to just a general search for it. and it list the 8.5/8.6 g.m. rears. but when you go to the app guide it only list chevy cars..

 

For those too young to remember, catalytic converters were federally mandated starting with the 1975 model year. GM went to single exhaust and one converter exclusively on these cars, thus the single hump crossmember for 1975-up cars.

 

True.. and With the car 42 years old.. adding true duals with no converter, is not 100% on the level with epa legal fed laws.. Neither is true duals and 2 converters.. So, I will not bother..
Been There done that.. Back when this state tested my 86SS I spent the money and put true duals on it.. with 2 converters in the OEM location.. running both pipes over to the pass side, then 2 converters and then back to two mufflers and out to the tail pipes.
And it failed the smog test. eye ball test.. it passed the sniffer, but because it was not the factory exhaust routing , fail..
At the time the 2 high flow converters and exhaust was 890.00 .
To keep the emissions clean only to be told.. sorry.. here is your inspection sticker with a big fat "R ..
I'll take my chances.. as the laws are well , stupid.. Oh you doubled the converters surface area.. for the same emission flow.. and put the converters in the same spot as the oem.. sorry.. it is cleaner out the tail pipes but sorry.. you fail..

 

Yes, and while this sounds crazy, there is some science to it. The car's emission control equipment was certified in a specific configuration, and that certification includes a lot of transient conditions, such as cold start. A single converter heats up and starts working much more quickly than two converters, thus if the car was certified with only one it will fail a visual inspection (and likely a cold start test) if you have duals with two. Keep in mind that state emissions inspections are only spot checks at a couple of operating conditions and obviously don't test all the conditions that the car was certified to. The ASSUMPTION is that if the car passes the spot tests and the factory equipment is in place, the system is working as intended. This is obviously not always the case, but it's a trade-off of practicality vs. absolute compliance.

 

I get that and totally agree, BUT we have come a long way in 40 years..
Todays converters are much better at scrubbing the exhaust than the 75 pellet type.. if you buy a quality converter.. And I'd be good with spending the money if , 1) they still tested these cars .. and 2) they pass/fail you by the sniffer not someone looking under the vehicle and say'n that isn't how g.m. did it so fail.
Most of us want to do what we can for clean air.. but the laws have to be fixed .
If today they tested my truck with it's efi. and converters it fail.. even when it is 4-5 times cleaner than the original set up..


This car has had a "test" pipe since 1977 ..