Just did some horse-trading and ended up with what I was told is a 57 312 from a Bird. It's paired up with a T10 made floor shift in a 54 Customline. Already went through the Hell of trying to find a reman dizzy for it, and ended up getting it running smooth on new points, condenser, and coil. Haven't pulled casting numbers yet, and now think it might be a '56 312 instead. Found a dual-diaphragm tach drive dizzy buried in all the extras in the trunk. NAPA owes me one for a big cust service foul-up on their part, and has offered to reman my dizzy for free to make up for it. Should I bother, since carb has been upgraded and it won't work the 56 dizzy znymore anyway?
Every Y-block engine for sale is a "312", or "from a Thunderbird",
just like all those GM V-8 engines for sale are "from a Corvette".
If the block could have been from a '56 or '57 Thunderbird the casting number will be just above and left of the oil filter. (photo) And it will have a prefix of "ECZ" with an A, B or C suffix letter.
Blocks from another foundry or earlier/later years will have the number in other locations with different prefixes. When you find the casting numbers on the block, heads & intake run them past the charts at these links...
http://ford-y-block.com/technical.htm
(the same site
Tinker &
miker98038 posted above)
http://www.y-block.info/casting/intake.html
A '56 tach drive distributor is worth a fair amount more than a regular '56 dist, but only to a '56 T-Bird owner who broke one beyond repair and doesn't want to upgrade to the '57 version.
They'll probably prefer their own rebuilder anyway, so sell it As-Is and keep the Big Favor the NAPA store owes you. You'll want it for something much better than an out-of-date distributor you aren't keeping.
If the distributor you have in the engine is '57+ it will have a notch to index the rotor. (photo)
Too many oem Y-block distributors sent to chain auto parts stores for rebuild/exchange come back not fitting correctly because the replacement drive shaft is too short to reach the oil pump shaft or cam gear properly. (photo)
.
... it’s a little tough to verify a 312. The spot on the crank is generally good, but dropping the pan and checking the main caps is the bullet proof way. Then you just guess at any overbore.
Two *ID a 312* photos below and this link, FYI ...
http://ford-y-block.com/identify312.htm
It is possible for someone to turn the mains of a 312 crank down to fit in a 292 block and bore it to 312, but the chances of finding one of those is beyond infinitely small.
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