1955 what engine block ID ECZ 6015?

Thank you very much. Are their any differences between the two motors. Like carberators, or where the fuel bowl filter is located. The fuel glass bowl filter on my car is located in front of carberator towards the driver side. Are there any other things i can use to determine engine size? i do not plan on tearing this motor down. Thanks


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Identify the engine further to eliminate the 292 engine block. According to Precision Engine Tech, to identify the 312 externally, check the flywheel flange on the crankshaft. The 312 ECZ crankshaft has a small dot on the outer edge. Check the casting number on the main cap if the engine is disassembled. ECZ is cast into 312 main caps; all others are 292 EBU caps.


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the main difference to me is the rear main seal design which differs between the 312 and the other y-block engines.
What is your vin?
Which carburetor do you have?
What transmission do you have?
the above can gove you clues but the only definitive thing I know of is the rear main seal. I am sure there are other tells but I do not know them. Also the heads may give another clue.
good luck ,J.


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What engine is in my car, block # ECZ 6015?
There is not a quick external check. The block casting number, over the oil filter and below the block head line, is a semi decent method. If the number starts with ECK, it is not a 312. If the number starts with EDB, it is probably 292 with a very small chance of it being a 312. If there are not three capital letters starting the number, it is not a 312 and is probably a later 292, around 1959. If the casting number is ECZ, you have about an 80% chance it is a 312, but it could be a 292.

The only ways to tell for sure are to either take the oil pan off, take the heads off and measure the bore and stroke, or take the flywheel cover off and try to get a look at the back of the crankshaft. Of the three, the flywheel cover is the easiest. You have to look at two things. First, find the semi circular cutout in the crankshaft flange at the flywheel. Second, rotate the engine 180 degree. If it is a 312, there is a recessed area on the flange with a raised circle in the center. If there is nothing on the recessed area of the flange, or something else other a raised circle, it is not a 312.

I work at the Preservation/Restoration center of the Crawford Auto Museum and I rebuilt a 292 engine from a 1955 Thunderbird. Since I had the crankshaft removed from the engine, here are photos of the crankshaft flange and the block casting number.

Since the block casting number starts with ECK, this is a 292 engine and not a 312.

Also, since 180 degrees from the semi circle cutout in the crankshaft flange there is something other than a raised circle on the recessed area, this indicates that engine is a 292 and not a 312.

I hope these pictures help you with your engine identification.

1955 Thunderbird Blue
Casting Numbers.jpg Crankshaft Flange.jpg Recessed Area.jpg
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