70 GTO question

[musclecarz]

I have only seen 2 actual VOE cars and both were GTO's and one was a chrome bumper car, The option was quietly promoted for obvious reasons. There was a vacuum actuator on the rear of each muffler much like the vacuum motor on a Chevelle Cowl flapper, Late in 1969 Pontiac made a TV add that ran during the superbowl, It showed a GTO rolling thru the drive-in, The driver reaches down and pulls the cable under the dash much like the RA cable and the exhaust note picks up and heads turn in the drive-thru!! Very cool, But Alot of people watching the Superbowl were not impressed,Including Pontiac Exec's, and the Monday after the Superbowl was the last day for the rare option. NOS parts for this option are very rare and most of the time must be hand made. I have seen only a few scattered parts NOS through the years and never an actual muffler, There's a repo project for someone!!

[Tom Hand]

Judge Man,
I am building some new "VOE GTO" mufflers and would love to have copies of anything you might have regarding them. We are building them in other sizes to enable them to work a bit better when open.
Please, if you are still on this site, contact me if you do not mind.
Thank you.
Tom Hand

[Belair62]

Damn...you Pontiac guys are getting the heavy hitters over here..I remember Tom on the Pontiac sites ? Welcome...and that would be an unbelievably cool option to reproduce

[Tom Hand]

Belair62.
They are really cool. Sound slicker than heck too. We have a set on a 69 CJ 428 Torino, a 55 Chevy, and on a OEM GTO 70 VOE car. Two more sets go to real VOE cars, one on another GTO and another on a street rod and the final ones on a Truck.
Very labor intensive to make for sure but cool to have. I can get them together with up to 2.5" in and out where stock was 2" in and 2.25" out.
I have several photos. This set is a one-of-a-kind, offset-center, 2.5" in and out and they are on the Torino.
Tom

[Belair62]

How do these work Tom ?

[442w30]

I wonder which RAIV GTO VOE you speak of? I ask because I know of one and it's a dealer-installed car. I'd be willing to bet this is the same car.

[Tom Hand]

BelAir, they use a former heater/ac vacuum actuator to pull a rod that opens a valve inside the muffler letting the exhaust bypass two of the pass tubes internally. Essentially, it is like running a straight pipe and a very very quiet perf. muffler and being able to switch between them using a vacuum switch.
Tom

[Tom Hand]

And here is a bit of data on how the 2" in, 2.25" out versions worked on my 69 340 Cuda and a shot of the car they are on, a true 70 VOE GTO four speed.

1969, 340 cu. in. 10.5:1 Chrysler engine in Plymouth Barracuda with 2.25” stock, 1969, 340 tailpipes with large rectangle chrome tips, measured at 10 feet from tailpipe outlet.

Closed Open
Idle (700 rpm) 68 dBA 78 dBA
2200 rpm 81.5 dBA 92.5 dBA
3500 rpm 88 dBA 99 dBA

They sound very good.

[Tom Hand]

Belair62, here is a closeup shot of the inlet so you can see the actuator and how it attaches.

[Tom Hand]

And here is the shot of the mufflers from the rear so you can see the spring portion; stand by for one more from the front.
Tom