Black76

Hello all,
I've got a question about dual exhausts. My '76 came with a single exhaust like most did. I would like to put dual exhausts on it. Upon looking underneath the car, I saw that the transmission shift linkages are right in line with where a left exhaust pipe would traditionally go. I know there are double hump crossmembers on the earlier cars, but I'd like to avoid replacing that if possible. Could I run the pipes closer to the outer edges of the frame? How have you guys run your pipes?

Thanks

joe_padavano

The equalizer rod from the frame to the trans is the same part number from 1973-1977 on the A-body cars, and dual exhaust was a factory option in 73-74.

redoldsman

Go to a good muffler shop and they should have no problem installing duals. I think it will be very difficult without the double hump crossmember.

Black76

I was afraid of that. I don't have a lift or even a transmission jack to hold up the trans. while I swap out crossmembers. I'm working out of my garage, so I don't have access to a lot of air tools.
Are the crossmembers bolted in or riveted in? I think on my pickups they're riveted in.

I was hoping I'd be able to run the exhaust pipes along the frame rails, but maybe that's not advised.

joe_padavano

All you need is a normal floor jack and a short piece of 2x4. You're not removing the trans, just lifting the back of it enough to take the weight off the crossmember. The crossmember is bolted in - it has to come out to remove the trans. And you should plan on running the pipes exactly where the factory did on the 1973-74 dual exhaust cars, which is not along the frame rails. Don't overthink this. GM did all the engineering for this almost half a century ago.

Black76

Thanks for the info. I will see if I can locate a double hump crossmember locally.

herkguy

Pm me for a guy in Iowa that may have some parts for you, I’ll give you his info. I know he has several years of different parts, he may have one for you.
eric

Greg Rogers

If you are taking the car to a exhaust shop for a factory type dual exhaust, (which is what I would do also), why not just get a dual hump crossover and ask them to install the crossmember while they are bending/installing the dual system?

redoldsman

That is a good suggestion Greg. They will have it on a lift and it will be easy for them to do. It will save you a ton of frustration. It might be a good time to change the transmission mount.

Black76

Those are great suggestions. I think that is the route I’m going to take.

Inline

G-force sells dual-hump crossmember for your car, and Summit aswell. Atleast on some point the Summit crossmember was actually G-force, just cheaper. Go figure.

You need to enlargen the bolt-holes at frame a bit, but otherwise its a bolt-on deal. And its not touching shift-linkages / anything if factory-routed. That is, if you cant locate factory dual-hump crossmember, or dont want to fabricate your own.