Will I need different exhaust manifolds to convert from single to dual exhaust on a 70 Cutlass 350 cu in. ?

Thanks-

 

You will add a cap on the right manifold where the crossover pipe presently connects, as the factory did. Pipes will run off the rear connection of each manifold. Cap is readily available or you can make one.

 

Thanks, appreciate your help-

 

Good upgrade, picked up .4 tenths and 5 mph in the quarter mile on a 2bbl. 350. That single exhaust really chokes that motor.

 

Ditto to dragline. My 350 2 bbl also felt much better in the “seat” with the dual exhaust upgrade. On mine, we capped the extra pipe and did not need new manifolds. It will sound so much better as well what are you using for mufflers?

 

Good question, what do you guys recommend for mufflers? I want a little "sound" not too quiet not too loud-

thanks

 

Walker Dynomax Super Turbo long case is a popular choice. Muscle car sound, not too loud, no drone, low restriction. There are others that people like as well but I find this muffler(s) a great combo.

 

X2 on the Dynomax. This is what I installed when I switched to a single to dual exhaust. But I changed the factory exhaust manifolds to Thorntons exhaust manifolds so I can install 2 1/4" pipes that I bought from Inline Tube.

 

Thanks, appreciate the recommendations everyone-

 

Yeah, X10 on the Dynomax Super Turbo mufflers. They come in three lengths 14",16", & 20" so you can pick your sound level, although even the 14" is still very mellow. Super Turbos give you the 'sound' without all of the 'noise'.
http://classicmusclecarexhaust.com/p...turbo-mufflers

 

I had not seen the 16" ones before. I use the 14" ones on all my 442s. I've got the 20" ones on my 67 Delta. To be honest, I didn't find a lot of difference in sound. And yes, the 14s are quite mellow. Certainly not the obnoxious (no)Flowmaster sound. How Flowmasters can be so obnoxiously loud while simultaneously being among the most restrictive in magazine flow tests remains a mystery to me.

 

Question Joe- Are you running straight duals, X-pipe, or H-pipe on your 442's and have you ever experienced Super Turbos getting louder with age? Some have suggested that they do but after 10+ years the 2.25" 14" on my Chevelle never got any louder. Flowmasters are an interesting muffler to me. They owe their success to a certain sound, and not really on superior flow numbers. Their chamber design allows the bass tones to come through, tones that are generally lost with straight through or turbo style mufflers with internal packing material. People love the FM sound, and the lower flow numbers are really not going to impact a street driven car. They've done a nice job in my opinion with the 50 and 70 series which keeps the traditional FM sound, just at a lower level and reducing/eliminating the dreaded Drone.

 

Straight duals on all of them. Mufflers with fiberglass typically DO get louder with age as the 'glass burns out. The Dynomax mufflers are all metal and do not have any fiberglass insulation.

EDIT: OK, I lied. This diagram clearly says "fiberglass matting". They didn't used to have fiberglass. I guess I don't have any long term experience with the newer ones.