Tim Gilliam

It came with a single exhaust. I want to put dual exhaust on it. How possible is this? I talked to my exhaust guy the other day and he wasn't sure because he said something about the tranny support might be in the way. Has anyone done this before and can you give me some idea's on what I am in for when I do this?

Eddie Hansen

I would think at worse you would need to find a 73 cross member I am not sure what year they switched from dual or single I know my 69 came with the double hump regardless of single or dual exhaust , I know/73 and 74 came with real duals but might have had specific cross members

joe_padavano

The 1973-1977 A-body cars used the same basic frame and the 73-74 cars were available from the factory with dual exhaust. Simply get a "double hump" trans crossmember from any 1973-74 GM intermediate (Cutlass, Monte Carlo, LeMans, Regal, etc) and it's a bolt-in.

Tim Gilliam

Do I need to worry about it being a TH400 tranny or are they universal between them and the TH350's?

joe_padavano

Crossmembers are the same. It wasn't until the A/G body cars (1978-88) that different crossmembers were used for different transmissions.

Tim Gilliam

So where would be the best place to get one of these and what am I looking for? Is it just a double hump on them?

Is there anything weird about the exhaust itself that I will need to worry about besides this?

joe_padavano

To clarify, EVERY 73-74 A-body came with a double hump crossmember, since dual exhaust was an option. You're stuck looking for a used one from the usual sources.

Again, dual exhaust was an option in 73-74. Get the pipes for one of those cars with the same engine. If you have a 350, you'll need to cap the crossover port on the passenger side exhaust manifold. If you have a 455 you'll want to swap to the W/Z manifolds.

Tim Gilliam

Okay junkyard shopping I will be doing.



Can you explain to me why? I was planning on using the stock manifolds and cutting somewhere down below the engine. My muffler guy mentioned something about maybe needing a new manifold for it. I'm at a loss as to what changing the manifold would gain and if I am why not just go to headers(which I really wasn't interested in doing).