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I just picked up a 2bbl holley, I think the part number is 12r 3975 b, I might not have the right number there though. My question is: The lower set of butterflys is not opening very far. I can't see anything that makes them stick on the outside so I was thinking its somthing on the inside that prevents them from moving. I don't have a rebuild breakdown sheet or the money to buy a holley book at the moment. Any help is much appreciated all, thanks for your time.
-Harribos
If the idle adjustment needles are turned in all the way, they will block the bottom butterfly from opening. Also, if you intend on doing a rebuild on that carb, be careful and check that you get the right rebuild kit. I just finished rebuilding one and none of the gaskets in the kit fit properly.
Either call Summit at 1-800-230-3030 and ask for advice on the kit you need or go to www.summitracing.com and search in their online catalog. The people that answer the phones are pretty knowledgeable and should be able to answer any question you have.
Thanks for your replys folks, its much appreciated.
-Harribos