I am getting ready to have true dual exhaust installed on my 1977 Delta 88 pace car and have a question about the transmission crossmember. These cars never had dual exhaust as an option so the crossmember is only a single hump on the passenger side. The muffler shop I inquired at said they could route the two pipes on that side or modify the existing crossmember to become a dual hump (at extra cost). Crossmembers.com has a bolt-in replacement for these cars with the Turbo 350 but it costs $485. I have one of their dual hump crossmembers in my 1979 Hurst/Olds and have never had an issue. The exhaust looks like the factory could have done it. So here's my options:
1 - Route both pipes on the passenger side and don't touch anything else.
2 - Have the shop route the driver's side under the crossmember so it hangs down low (and looks bad)
3 - Modify the existing piece so it becomes a dual hump
4 - Buy the new dual hump piece and have them install it to do the exhaust the right way.
I'm looking to do a 2.25 inch system with quiet (stock-type) mufflers- nothing outrageous. As I get older I realize that my days of loud exhaust systems are over. The shop can also remove and block off the crossover pipe.
I've always felt that ANY engine 350 cubes or larger should be running true dual exhaust for better breathing.
What's my best option?
I

 

Back in the late 1980’s we modified the cross member on my dad’s 1977 2 door 98, essentially the same car. We put a 455 in it. The car is still in the family and the cross member is fine. When I do the same to my PaceCar, I will modify the cross member. Just my 2 cents.

jerry

 

I am leaning towards number 3. I’ll probably just have the shop modify the existing crossmember.

 

My 87 442 had the hanging under the crossmember 2nd pipe, looked like absolute crap.

Eventually had it notched and boxed and never regretted it. What matters most is that its a highly competent shop and that you trust them. I think it cost me 50 bucks when I had it done. But that was quite some time ago.

I'm with you as far as the noise from loud exhaust goes. What I found so badass in the 70s 80s and 90s, is too much for me today. The last time I had my exhaust updated I went back to factory generics, for mufflers. (But I do still want the oomph...)

And you are absolutely correct about chunky Olds V8s and true dual exhaust. Single exhaust detunes our engines. Proven by the factory themselves.

Anyway, here is a solid example of a boxed notch from the internet.

Thank you to EricVonHa of the Impala SS Forum. Post #27 here https://www.impalassforum.com/thread...1320530/page-2

 

I'm in the process of putting duals on my 75 Delta Convertible and are going to have the shop alter the crossmember. Can;t wait to see it finished

 

I was talking to a buddy while spinning wrenches on his car last night.
He came up with a cool idea option. Like you, my car has the single hump and big open area for that pellet style converter.
His idea is bring both front pipes off the manifolds, over to the pass side then put the X pipe where the converter was, then two pipe out to mufflers then tail pipes.
No need for a 400.00 crossmember or cutting/welding The stocker. And you gain the X pipeto mellow out the tone.

 

I modified my crossmember and it works just fine. It’s not difficult and can be handled pretty easily. If you find your way to the “Cape” bring it along and I’d be glad to help you out.

 

Getting a crossmember from a 90's Impala SS would be my solution. I have a couple, but Chicago is far away. I'm not sure this could be done without some minor corrective surgery.

 

I had thought about a crossmember from an 90's Impala SS or Buick Roadmaster, both of which could have dual exhaust from the factory. The only issue is that the cars only came with the 4L60E transmission and not a TH350. The mounting point would be different . Might be more of a hassle to get it to fit properly. I'm just going to have the shop modify the existing crossmember. That seems like the easiest choice. The place has done quality work for a while so I'm sure they can handle it.

 

👍

I just uploaded a series of short videos, of my rides current exhaust. Which matches your wants. Just some idling and revving. With plenty of written details.

https://classicoldsmobile.com/forums...ds-etc-187428/