Mark.  Click the link below to see a 'B' manifold that recently was sold on eBay.  When the eBay page opens scroll down on the page to see the complete advertisement from the seller.  Put your mouse over the 1st picture to enlarge it to get a close-up of the rear on the manifold surface behind the carburetor mount.  Notice the casting date code 67 followed by an upside down E below the 'B' casting number.
http://www.ebay.com/itm/Ford-Y-Block-312-292-272-Thunderbird-Holley-4-Barrel-Intake-4v-Fairlane-/302231813424?_trksid=p2047675.l2557&ssPageName=STRK%3AMEBIDX%3AIT&nma=true&si=UqmL9e5n7yEU2Inu8iWpLk3%252FfE4%253D&orig_cvip=true&rt=nc


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

Merc continued to offer 312 engines for '58, '59, and 1960.  I can't remember if they still came with single 4 barrel carbs after '57.

Ford used the 'B' manifolds on some of the heavy duty truck applications with 292 engines up into the '60s, I think.  None of the pick-up trucks with 292s had the 'B' manifolds that I'm aware of.  I've got one later truck application 'B' manifold that does not have the heat tube running through it for an automatic choke.  I suspect that the truck had a manual choke or a heat tube that ran to the passenger side exhaust manifold.

I'm not up on date code reading.  'B' manifolds that I've seen with the date code had the code adjacent to where the ignition coil was mounted.

Trying to help on this, but my information is flimsy. 


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

We're not all "B" manifolds 57 only? I don't remember a 58 or newer Y having one. The FE style engines came out and the Y moved back. Same for the 312? I could be wrong and often am.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

There's an Ad on Kijiji from someone looking for a B Manifold but He wants One that is correct  for 1957. Is there a casting # or any way to identify what Year these Manifolds were made for? I don't remember seeing anything like that on the One I have.