3 x 2 linkage setup

[Frank/Paula Lowery]

We own a 69 427 with the 3 x 2 Holley setup (original). The carbs were sent off to be rebuilt/replated. The linkage was misplaced so a new linkage was ordered from Paragon. Here is the problem. The front rod is a fraction to long, even when adjusted all the way in. This causes the front carb body to open when connected shooting the idle speed to 2500 rpm. The rear carb rod is a fraction to short, also slightly opening the throttle body when connected and causing the idle speed to shoot up. Thanks in advance for any help.

[JOHN MELVIN]

Re: 3 x 2 linkage setup

Have you tried switching the front and end carb linkage rods?. You may have them backwards

Also, ensure the rods are adjusted as:

With center carb wide open (have a friend hold it wide open for you). The center carb must be wide open to make the linkage rod adjustements. With that done, ensure the end carbs linkage pivot point sits on the bottom of the center carb slot, and hold the center carb wide open :

Rear carb rod should be adjusted so the rod end (the part that makes a 90 degree angle), falls 1/2 the diameter of the rod itself, toward the center carb, in the rear carb linkage hole. In other words, the rod will look like it just falls short of entering the rear linkage hole, by half the diameter of the rod itself

The front should be adjusted so it just falls short of plopping in the hole

If in doubt, adjust both so they fall just short of entering the hole. Yes, it will make it so the end carbs are just slightly open, as it should be

[Dennis Rosenthal]

Re: 3 x 2 linkage setup

John, The end carbs should not be open at idle. the purpose of the linkage is to CLOSE the end carbs when throttle is released. I set the idle on 3X2 cars sometimes with linkage removed, and then adjust the linkage to ensure end carbs are not opening at idle. Dennis

[JOHN MELVIN]

Re: 3 x 2 linkage setup

DENNIS. I READ IT IN THE AIM, AND THE ORIGINAL 1968 SERVICE MANUAL. JUST RESTATING THE PROCEDURE, AND I HAVE MY L68 ADJUSTED THE SAME.

I MAY BE MISTAKEN IN SAYING IT SLIGHTLY CRACKS OPEN THE FRONT/REAR BUTTERFLYS, BUT THE ADJUSTMENT I STATED IS CORRECT