(2) Holley 450/500 cfm Carbs

I am at the point now where I need to locate two Holley 450/500 cfm carbs for my cross ram setup. I am looking for either exc. rebuildable cores or if you have a pair that are fresh and are a matching pair, I would be interested. So, what do you guys have out there? I would be willing to consider any other mnfr carbs in that range as well.