I posted this in 2013
Gentlemen:
Beware of this problem (perhaps someone has had this experience), Saturday afternoon while having a relaxing drive with my son, the engine of my car started to rev up excessively. So as to avoid blowing the engine and place ourselves in a very dangerous fast driving situation immediately I turned the key off and coasted to the shoulder to inspect the problem.
At first glance all seemed normal the idle adjustment screw of the Holley 770 carb was fine, the choke was not sticking, nothing was binding preventing the carb to function normal, but each and every time I tried starting the engine it went up all the way to 3500 rpms. I had the car towed home and with fingers crossed that nothing major was going on.
Yesterday we started checking things around and eventually I decided to pull the carb off, to our amazement, the gasket between the carb and the phenolic spacer center was broken and a tiny particle had lodged in between the secondary venturies throttle plates keeping them from fully functioning, hence causing the excessive elevated rpms.
The gasket fragment was removed and the carb operated normal, we installed back in the car and worked fine again.
My biggest concern was our safety when all of a sudden the acceleration went out of control, hence at the risk of sounding patronizing to anyone please be careful and enjoy a safe drive. Our cars could be very unforgiving due to their awesome power.
Sincerely
Lou