Topic: true dual exhaust w/o cat
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Anyone familiar with the dual pipe setup that MA advertises for an '81? MA states you don't have to change the tranny crossmember. This true?
SPONSOR AD:: (Our Sponsors help support C3VR)

Frederick, MD - USA
Joined: 2/20/2003
Posts: 548
Vette(s): Frederick County Corvette Club (Maryland)
Tan 64 365 Hp Conv 4 sp
Red 72 4 sp Conv ..running a '68 327
Blue 76 Coupe L 48 4 sp
White 79 Coupe L 82 auto
Silver 98 Conv, 6 sp
35th Anniv '88 vette
Not sure about the 81...IF the cross member has two holes in it you are home free...
I run True Duals (no cats ) on my 76 & 79 and my brother ran the same set up on his 80... BUT in either 81 or 82 The cross member was finally changed and the new one only had one hole for the exhaust pipes to go thru...
Bob G.
I run True Duals (no cats ) on my 76 & 79 and my brother ran the same set up on his 80... BUT in either 81 or 82 The cross member was finally changed and the new one only had one hole for the exhaust pipes to go thru...
Bob G.
Bob
64,72 & 98 Corvette Ragtops
76 & 79 & qa 88 ANC Corvette Coupes
Click on any image for larger view!
MA is correct. Your crossmember does not have two holes but the true dual setup they sell sends the left pipe over to the right side to run parallel to the right as it goes under the crossmember, where the indentation is. The left pipe then goes back over to the left side as it goes under the spring. You may have to have something welded to right pipe to accept the oxygen sensor. I don't think the MA pipe comes with the O2 hole. I forgot. If you wait for the MA Funfest and if you go there, you can order the pipes at 10% off and no freight; freight on a bunch of pipes is high. I am certain that someone from this forum will be going and can order them for you there in case you ar enot going. Good luck. I did this to an 82 and then put the catalytic converter back on because without the converter, the 02 sensor does not read the correct back pressure, I suppose, and the cruise control will not work. Same thing happens on a Saturn. Do not try to put an earlier crossmember with holes on your car; it ain't worth the headache and it will never be right because of the different bumps in the floor on your car. Been there and tried that also. OH6A 2007-08-31 09:11:59
C3VR Life Member #4
NCM Life Member #994
Vietnam Helicopter Pilots Association Life Member
NCM Life Member #994
Vietnam Helicopter Pilots Association Life Member
FYI, I offered my true dual setup on this forum a couple of years ago for free to anyone who would come after them; nobody came so I gave them to the iron man.
C3VR Life Member #4
NCM Life Member #994
Vietnam Helicopter Pilots Association Life Member
NCM Life Member #994
Vietnam Helicopter Pilots Association Life Member
You could also check with Allen Stainless. That's were my duals came from. They will bend them to fit your car. They have all the specs on file.

Manteca, CA - USA
Joined: 11/20/2005
Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
While I was writing, so was everyone else. Excellent dudes
.
Jimmy B.
Just can't wait to get on the road again.
Click to see larger views!

Apache Junction, AZ - USA
Joined: 10/15/2006
Posts: 285
Vette(s): 1982,150K,Renegade CFI,Hooker Side Pipes,85 fuel pump,Bilsteins,HD suspension, Aluminum radiator, SharkBar/w 5-Point Restraints. 3:73 gears coming soon.
OH6A,
Getting ready to do the "True Duels" on my 82 with a 79 cross member, headers, bullet high flow cats (Gotta have the cats in AZ) with Flowmasters; one cat has the bung hole for the O2 senser and will use a heater senser.
I have seen two other local 82's that have used the two hole cross member and all I have heard it the transmission mount hole needs to be drilled bigger, otherwise it is a direct fit. What kind of problems did you have? Nice to know everything before you get it all apart.
Thanks!
Phill's Vette 2007-08-31 21:18:30
Getting ready to do the "True Duels" on my 82 with a 79 cross member, headers, bullet high flow cats (Gotta have the cats in AZ) with Flowmasters; one cat has the bung hole for the O2 senser and will use a heater senser.
I have seen two other local 82's that have used the two hole cross member and all I have heard it the transmission mount hole needs to be drilled bigger, otherwise it is a direct fit. What kind of problems did you have? Nice to know everything before you get it all apart.
Thanks!
I put the MA true duals on my 81 with 4spd. It bolted up perfect and I think it came with the O2 sensor location drilled and tapped. Don't recall - I since have gotten rid of the O2 sensor, etc ,etc. True duals were an excellent upgrade!
Great info! Thanks alot for the speedy reply also, I knew I could count on you guys.
I have all the smog and computer sensors off as I don't have to have it inspected here in Tn. (antique tags). The cat is still there but the tube is cut and welded. I think I'll like the sound of the duals with mufflers if it isn't too loud, but I want to elliminate the heat buildup from the cat also.
Hey, you have that junk man's telephone number?
But more importantly, why did you get rid of them? Did you have problems or ???

in Forum: C3 Fuel, Emission Control, and Exhaust Systems
SPONSOR AD: (Our Sponsors help support C3VR)