gears,

Any of the big chain parts stores (Advance, Autozone, Pep Boys) sell adapters that will allow your Holley to bolt to the Carter/Edelbrock pattern of the Offy adapter plate. It's a really common piece. Probably cost you about 20 bucks, and it'll give you a 1/2 to 1" additional mounting height. That will help with throttle clearance issues, trust me.

So check one of your local parts chains or Ebay. They have 'em on there too.

-magic mike-