Originally Posted by rac43
I guess you all are trying to answer my question but I don't have a Holley, nor do I a have a Performer. I have a Elderbrock Square Bore Thunder carb. The secondaries DO NOT open more than 1/8th inch when the throttle is wide open. I thought someone here with experiance on a Thunder carb could offer me an answer. From the answers above, I now know what a Holley and a Performer card do. Anybody know anything about a Thunder Carb?
The Performer and Thunder series carbs share a lot of features, including mechanical secondary butterflies. The Thunder series isn't a new concept, they're a copy of the Carter AVS carbs that came on the 60's Mopars. I had one on my 68 Roadrunner that I bought new in 1968 after returning from Vietnam. You can see the features here:
If you read closely you will see the statement that I copied for my earlier reply. If your secondaries don't open fully when you rotate the throttle linkage to its limit, you should investigate the linkage for a problem.