GTO 3/2-BBL - Vacuum Actuated

[60sStuff]

Right side secondary arm operation.

End carbs were activated by a Vacuum Control diaphragm.

This “Control” mounted to the two RH rear carb studs and provided the pulling power to open the front and rear Rochester’s.

The two end carbs each had a small throttle return spring that clipped into the base plates to assist with deceleration.

The “Automatic” return springs #7013783 were twice the size of a “Manual Shift” spring #7029689 which (helped) on this Suicide Linkage.

I’ve seen many Original Vacuum Tri-Powers converted over to the Mechanical version and these springs were never changed out, because most are unaware.

[L_e_e]

I learned the hard way when I was a kid that on a Mopar Six Pack the carb linkage is to CLOSE the outer carbs.....

[njsteve]

Originally Posted by L_e_e

I learned the hard way when I was a kid that on a Mopar Six Pack the carb linkage is to CLOSE the outer carbs.....

Me too! I had the throttle return spring break on my 440+6 Cuda coming out of a toll booth on I-95 in Connecticut back in the day. Throttles opened and stayed open with all 6 barrels at WOT. Still in first gear at 7000 rpm, all I had time to do was click the igntion key off to kill the spark. The resulting backfire blew out the mufflers and the window(s) in the toll booth. The cops found me on the side of the road about a half mile away. Shaker was already off and I was scratching my head at what the heck went wrong. The Trooper was a car guy and handed me a couple rubber bands to rig it up so I could get home. No tickets!

[grantprix]

Great stuff, Chris!! I never would have guessed Trico made anything other than wiper parts.

[gtopillado]

Thanks for posting thread. Hey 60sstuff, I'm in SF Bay Area as well, curious if I know you? I have a 64 Black GTO w Tri Power. Was thinking of putting the vacuum secondaries back on my car but almost forgot how much I enjoy the ease of having mechanical, which I installed in 89'. My car was built in Fremont as well, First week of February 64'. Anyways thanks for post a great thread that will help future owners if they decide to go this route, very educational and spot on. Dave

[RPOLS3]

The knowledge base here never ceases to amaze me. Great summary - thank you.