Racing Beat lists 6 different flavors of their Holley Carb, based on engine size (12A or 13B) and porting (Non, 6-port, bridge port).

Odds are there are several variations in what they do depending on the specific application ordered.

 

Messed with it a bit more. It has trouble starting when the engine is cold. but as soon as it warms up, it runs great and hold a clean idle. But while it's still cold, I have to hold the throttle above 1500 rpm for it to stay running or it will stumble and shut off.

I'm going to pick up a set of #56 jets tomorrow and see if that helps the cold starting problem. I have 64's in there right now...

 

thats the reason why I always recommend a 48 IDA. Easy to tune and rejet to fit any tye of port, and for the most part, you only have to spend $$$ once.