Can anyone tell me what these two carbs were originally used on?

17082253 2951
17059206 2728 CB

I am looking for a Q-jet for my 400. Any one have any leads? Thanks.

first one, 1982 Olds 305-307.
second one, 1979 Chevy 350.

Neither one is good for your 400. I will sell you the carb off my car if you really need one that is already set up; I can rebuild my original. Or you can check seller j*s*s on eBay, they're local and should have what you need.