How to ID a 256 from other Y blocks?
 

Looking for some guidance. I'll soon be looking at a '54 Merc that the owner claims still has its original 256. Any tips on how to tell a 256 from other Y blocks? Thanks in advance.

Re: How to ID a 256 from other Y blocks?
 

According to Y Block expert John Mummert and listed in the technical information on his website


http://www.ford-y-block.com/Block%20identification.htm


The 1954 Mercury 256 would have a casting identification of EBY on the drivers side of the engine block up high where the heads would meet the engine block.


Good luck.


Oldmics

Re: How to ID a 256 from other Y blocks?
 

It will have an EBY prefix casting number on the block, this one was at the base of the distributor. If not there look just above and left of the oil filter.
The E suffix indicates the 4th design revision from original. This would loosely relate to the date the car was produced, later in the model year than a block with a B or C suffix.

An EBY prefix casting number will also be on the heads and rear runner of the intake manifold.
The spark plugs in this 256 were the smaller 14mm size with a metal crush gasket, not the tapered seat 18mm size used beginning in '55.
The choke thermostat is mounted on the passenger side of the exhaust crossover of the intake manifold. (very much like this '55 example, photo #4)

Re: How to ID a 256 from other Y blocks?
 

Also, the cylinder heads in '54 and '55 had core plugs on the front and rear surface. A quick glance to see that. Not a guarantee that they are original heads, but pretty good odds.


Sal

Re: How to ID a 256 from other Y blocks?
 

Here's what they look like...

Re: How to ID a 256 from other Y blocks?
 

https://www.fordbarn.com/forum/attac...p;d=1546419830

https://www.fordbarn.com/forum/attac...p;d=1546419830
I'm confused. I just had this 312 Y Block rebuilt. The top photo shows Cast Number on the Heads that came with the car, a 1956 Mercury. The second photo shows the rebuilt motor. You will see that these Heads have Core Plugs. In a previous Post, it says that the 55 and earlier Heads had these, but not the newer models? Are these the correct Heads for this 1956 Mercury Y Block? Not that I am going to change them now, but it would be nice to know the facts. I look forward to feedback on these Heads.

Re: How to ID a 256 from other Y blocks?
 

all 56 c heads i used had the core plugs.late ones didnt.

Re: How to ID a 256 from other Y blocks?
 

That's true. ECZ-C heads were used in '56 only and had the smaller combustion chambers for a higher compression ratio. They were used in early '56 production with core plugs, and later in '56 without core plugs.


Sal

Re: How to ID a 256 from other Y blocks?
 

This linked chart shows the ECZ-C heads were used in '56 for; Ford cars and light trucks, Mercury's and on 272, 292 and 312 engines.

I sold a pair of them a couple years ago. They didn't have the core plugs.
Must have been some sort of mid-year change...

http://www.ford-y-block.com/cylinderheadchart.htm
.

Re: How to ID a 256 from other Y blocks?
 

i tried to find out awile ago what month it took place but didn get an answer.im guessing the spring

Re: How to ID a 256 from other Y blocks?
 

My 56 Mercury was built in Los Angeles on the 4th October 1955, so it is an early build. That means the Heads with the Core Plugs are correct for my car. Thanks for the clarification.

Re: How to ID a 256 from other Y blocks?
 

I'm not sure if anyone can say for sure if there was an actual cut off date, or if they mixed it up. Pretty safe bet that your '56 Mercury has the original heads though.


Sal

Re: How to ID a 256 from other Y blocks?
 

The only thing to be positive about Ford production is, don't use the word positive. With assembly plants all over the country, and more than one casting plant, longer travel time makes different production dates. If two box cars were accidentally reversed, and unloaded on different days, so what. Use the parts you have.

Re: How to ID a 256 from other Y blocks?
 

Another change that happened somewhere between the '54 239's and the 272/292 '55 engines was an increase in size of the intake ports.
I'm not sure which port size the EBY 256 engines used. Maybe both, with early and late versions?
The 256 long-block I had was sold before I checked it more closely.