Comments on Changing Original Single to Duel Exhaust - 1978 with 440

[Sport Fury 67]

The original exhaust on my 17K mile 1978 with a 440 needs updating due to leaks and small holes. Instead of keep it factory, the logical thing at this point would be to upgrade it to dual exhaust. We have an excellent shop here in Chicago (Iggy's- no muff too tough). Is there any advice or comments from the usual suspects that have done this upgrade to their ride? I know you should make accommodations for the removal - maintenance of the starter. Anything else? Just want to return it to a quiet ride like when it rolled out off the line from Jefferson Assembly.

 

[CBODY67]

If your stock muffler inlet pipe size is about 2.5" diameter, you'll probably not notice much, if any, difference in performance with a dual system. The dual system (with 2.5" pipes and muffler inlets/outlets) will sound better, but might not really make a big difference in performance, all things considered. Be sure to use mufflers that are the same size as the original (normal Chrysler C-body size).

You'll probably end up with a "will-work" pipe hanger for the lh side, in front of the axle. Just use OEM-type hangers for best results. Many of them are in the back of the Walker Exhaust catalog.

Even the alleged best muffler shop can do work that has poor durability, by observation.

 

[commando1]

Don't weld all the couplings. Clamp then. I'm absolutely of the no crossover school but everyone else wants them.
A welded system with a crossover. Think about that if you ever have to drop the driveshaft.

 

[1978 NYB]

I have 2.25" pipes and Flowmaster 40's on my 78 NYB.

 

[75LandYacht]

I swapped my 75 NYB over to 2.25 duals as well. Flowmaster 50 series, sounds nice. Nice rumble at idol and low speeds, very quiet at Hwy speeds. I like it. I did “Turndown” tips just behind the bumpers edge.