[6d7gto]

What is the function of this wire like mechanism located on the underside (middle, toward front) of a Chevy throttle plate?

[goatman65]

I think its part of the adjustable part throttle.Is there a metal plug in the front of the plate? There is a screw behind the plug.

[Kenth]

All 1968-74 Q-jets uses this style APT , except Pontiac Q-jets wich instead used adjustable air supply to the idle circuit up to 1969 and adjustable air supply to the main circuit from 1970-74 for off-idle adjustments.
This adjustment on Pontiac Q-jets sits under the triangular washer on the vent tube.

["QUICK-SILVER"]

Originally Posted by 6d7gto

What is the function of this wire like mechanism located on the underside (middle, toward front) of a Chevy throttle plate?

APT like Kenth said, is adjustable bottom stop for the power piston. Sets how deep metering rods drop in jets under high vacuum. Adjusting screw is behind plug in front.

[Cliff R]

In almost all cases, that adjustment screw isn't moving without some help. We make replacment screws for them, by turning down the end of a #10-32 screw and adding a spring to it.

The best method I know of to get the old adj screw out is to heat up the casting carefully with a propane torch, lots of penetrating oil, and patience. Those screws are hardened and the ears snap off easily, then the are REALLY DIFFICULT to get out!......Cliff

[6d7gto]

Thanks fellas! Great info.