I just bought a 56 Victoria. It was sold at Barrett Jackson a few years ago as a 292. When I bought it it was also posted as a 292.
The serial number starts with an “S”. I read somewhere where it might be a 312?
Comments please. Thanks.

You sir, are a very lucky man -

READ HERE - http://1956-ford.com/1956-ford-car-data-plate.html#techservicebulletin

FORD used the ASSEMBLY PLANT CODE 'S' (SOMERVILLE, MA) in lieu (Fr.) of the VIN 1st CHARACTER ENGINE ID NO to ID these mis-assemblies for service/warranty.

U - 272
M - 292
P - 312

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Keep in mind that after 68 years, your engine might not be the engine that was in the car when it rolled off of the assembly line. Get the number off of the engine block (above the oil filter) and compare it to the ID numbers found on John's site (ford-y-block.com). If it's an ECZ block, it could be either a 292 or 312, in which case the search is not over. 

It is not the actual engine that makes the car, it is the PATENT PLATE (if correct to the car).

Even if not the original engine, that can be corrected. Not the VIN (if not falsified).

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If my memory is correct most 312's can be identified quickly by the dip stick, most are located on the passengers side of the block in the middle of the exhaust manifold. The 292's dip stick is located on the passengers side also but up front by the timing cover and water pump very close to the generator. It depends on the foundry where the bock was casted I believe. yes the ECZ numbers help also. 

Dipstick location is no indication of displacement.  Truck engines use the center location and certainly were not 312s.  T-Birds use the center location and are not all 312s.  The rest use the front location and can be any displacement.



Lawrenceville, GA

ALL SBC’s Corvettes and ALL Yblocks are 312’s …. Just ask any seller….

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

As Charlie said, don't go by the dipstick location to determine whether you have a 292/312. My 56 ECZ-A block has the dipstick near the center on the passenger side, and it is most definitely a 292. How do I know? I pulled a head, measured the bores, and found + .060 on top of the pistons. It's most definitely not a + .060 312. 

The dipstick location only indicates where the sump is on the pan.

Now if you come across one that has two (or more) dipsticks, that would cause concern.

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This thread from 14 years ago is on point, especially Ted's post: 
http://forums.y-blocksforever.com/Topic47706.aspx