450 cfm holley carb?

I was going through my storage today and found this carb, I didnt know holley made a 450 cfm carb. I dont even know where the hell i got it from. Did these come on somthing from the factory? Im thinking that might be the perfect size carb for my y-block

 

Most I've seen had factory ford part numbers. I've run them in dual quad applications for years.

 

I have one I searched the numbers and they came up as a late 70s early 80s malibu wagon or sedan.

 

fantastic dual quad setup, 16 MPG on my 301 tunnel ram FC Holden

 

anyone wanna buy this one, i just picked up a edelbrock 500 for my truck. so i dont need it.
wes