General Questions Place to post your questions that don't fit into one of the specific forums below.

70 Cutlass Single to Dual Exhaust Conversion

Thread Tools
 
Search this Thread
 
Old July 21st, 2019, 05:11 PM
  #1  
Registered User
Thread Starter
 
4-Speed's Avatar
 
Join Date: Dec 2009
Location: Northcoast, Oh.
Posts: 282
70 Cutlass Single to Dual Exhaust Conversion

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

Thanks-
4-Speed is online now  
Old July 21st, 2019, 05:30 PM
  #2  
Registered User
 
bccan's Avatar
 
Join Date: Feb 2009
Location: West Hartford, CT
Posts: 1,497
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.
bccan is offline  
Old July 21st, 2019, 06:10 PM
  #3  
Registered User
Thread Starter
 
4-Speed's Avatar
 
Join Date: Dec 2009
Location: Northcoast, Oh.
Posts: 282
Thanks, appreciate your help-
4-Speed is online now  
Old July 22nd, 2019, 12:32 AM
  #4  
Registered User
 
dragline's Avatar
 
Join Date: Jan 2018
Posts: 405
Good upgrade, picked up .4 tenths and 5 mph in the quarter mile on a 2bbl. 350. That single exhaust really chokes that motor.
dragline is offline  
Old July 22nd, 2019, 11:45 AM
  #5  
Registered User
 
tsgutlass's Avatar
 
Join Date: Jun 2019
Location: Oregon, WI
Posts: 131
Exhaust

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?
tsgutlass is offline  
Old July 22nd, 2019, 05:40 PM
  #6  
Registered User
Thread Starter
 
4-Speed's Avatar
 
Join Date: Dec 2009
Location: Northcoast, Oh.
Posts: 282
Good question, what do you guys recommend for mufflers? I want a little "sound" not too quiet not too loud-

thanks
4-Speed is online now  
Old July 22nd, 2019, 09:44 PM
  #7  
Registered User
 
bccan's Avatar
 
Join Date: Feb 2009
Location: West Hartford, CT
Posts: 1,497
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.
bccan is offline  
Old July 22nd, 2019, 10:00 PM
  #8  
Registered User
 
ELY442's Avatar
 
Join Date: Jul 2009
Location: Brooklyn, NY
Posts: 2,009
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.
ELY442 is offline  
Old July 24th, 2019, 03:28 AM
  #9  
Registered User
Thread Starter
 
4-Speed's Avatar
 
Join Date: Dec 2009
Location: Northcoast, Oh.
Posts: 282
Thanks, appreciate the recommendations everyone-
4-Speed is online now  
Old July 26th, 2019, 01:50 PM
  #10  
Registered User
 
Spoffie1962's Avatar
 
Join Date: Dec 2017
Location: PA
Posts: 14
Originally Posted by ELY442
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.
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
Spoffie1962 is offline  
Old July 26th, 2019, 05:46 PM
  #11  
Old(s) Fart
 
joe_padavano's Avatar
 
Join Date: Mar 2007
Location: Northern VA
Posts: 48,229
Originally Posted by Spoffie1962
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.
joe_padavano is online now  
Old July 27th, 2019, 07:29 PM
  #12  
Registered User
 
Spoffie1962's Avatar
 
Join Date: Dec 2017
Location: PA
Posts: 14
Originally Posted by joe_padavano
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.
Spoffie1962 is offline  
Old July 27th, 2019, 07:41 PM
  #13  
Old(s) Fart
 
joe_padavano's Avatar
 
Join Date: Mar 2007
Location: Northern VA
Posts: 48,229
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.

joe_padavano is online now  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
razman427
Cutlass
13
June 13th, 2018 04:42 PM
dalilama
Small Blocks
27
June 30th, 2016 11:37 AM
ragtop71
General Discussion
10
May 4th, 2011 04:25 PM
nukesec1
General Discussion
5
December 12th, 2009 11:59 AM
Delance318
Small Blocks
11
June 15th, 2009 10:19 AM



Quick Reply: 70 Cutlass Single to Dual Exhaust Conversion



All times are GMT -7. The time now is 05:24 PM.