59 RB 383.Either from a Windsor or Saratoga.?
Guess I'm a little late.

It's from a Windsor 62, but correct, could have come in either in both 59 or 60. What freaks out most people is seeing a 2 barrel intake on an RB engine

Something I learned recently was that Chrysler bought some of Packards tooling when they went out. For the Chrysler Big Block the Big Wigs told the engineers "build us a new engine whatever way you want but this is the bore spacing"

So for 30 years and countless engines,Maxis,Hemis,383s,440s whatever they all have Packard to thank. Chrysler got a good deal on some tooling and they ran with it.

Thank you Packard

Here's another abandoned port, save the casting, add a plug theory. This is a 64 426 Street Wedge carb that utilizes the newer style side mounted automatic divorced choke, the "tube" in the front where the older choke existed is plugged from the factory. I believe that port was for the front mounted choke the early AFB's had.

I think old AFB's from late 50's and early '60's Cadillacs had some funky "choke" thingy up there.
I got one of those old carbs somewhere. I'll see if I can find it.
Might as well have a history lesson here eh?

Here is a 3251 from a 62 413.

You beat me too it Maxie, here's a 3251 I have laying around as well.