I was the one that bought the engine Buzz posted about in the Racing Section a couple of days ago. As Buzz said in his thread, all markings have been ground from it and I would like to make sure I know what I have. My plan for the engine is to put it in a '57 T-bird and while I don't mind performance enhancements, I would like to make sure it is reliable and streetable.
Now for the questions-

 For the crank, it doesn't have the aspirin mark, has a EC marking, a 15/16" hole on the front counterweight, and the rods are EBU so from what I have read, all of this checks out as a 292. Is this correct?

It looks very clean and has what looks like aluminum pop up pistons. I think they are aluminum because they are non-magnetic. Does anyone recognize the pistons? I am trying to understand if I am going to end up with a high compression ratio  if I put this back together as is.

The heads are ECZ-G heads and it looks they have stainless exhaust valves and some mild porting, but the rockers needs a little clean up. 
Based on what can be seen from the limited pics and info so far, could this be a good match for my needs or should I consider a piston swap?
Here are a couple of pics and I can get more if it helps pin things down a bit.

The crank is 272 or 292.  Measure the cylinder bores.  You will need to know the combustion chamber and dome volume, as well as the thickness of the head gaskets that will be used and the relation of the top of the piston to the surface of the block (in or out of the hole and by how much) for a static compression calculation.  The heads can be cc'd.  I don't know what the procedure is for piston domes but I'm sure there is a way to determine that as well.  Some head gasket volumes can be found here:  https://www.eatonbalancing.com/2012/06/30/head-gasket-volume-calculation/

Once you have all of that, you will also need to know which cam you will use and the specs, which is used to determine the dynamic compression in order to determine if it will run on pump gas.

These are things that a machine shop can help with if you don't have the tools or know-how.


Lawrenceville, GA

The chambers  have been cut to match the piston domes, you must measure the chambers to know what you have, the pistons will hit a standard head.

The rocker arms (they start with 575) are the 1.43 ratio, not the 1.54.  Unusual for a "G" head


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

By today’s standards typical 292’s were low compression. 8 - 8.5 to 1 with shim style original gaskets. I’m the type who would make a plaster mold of the piston top and cc the head myself because I have the tools. I use the compression calculator on the KB piston website: you need to know a lot to be accurate. I would love to have a 9.5 to 1 292+” Yblock. Good luck..

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

Thanks all for the input and once again I find myself in over my head on Y-blocks. My original plan was to take it in to the local machine shop (they seem to speak Y-Block) so I should be able to get things sorted out with them. However, I do want to educate myself as best possible going in to them so I can ask the right questions and try to understand what they are saying. 

Charliemcraney, thanks for the 272/292 bore info. Buzz measured it at 3.77" and the machine shop will confirm. Thanks also for the chamber  compression ratio info. I have done static calcs before but will need to look into dynamic CR.
Cliff, Thanks for that and I'll talk it over with the machine shop to make sure we understand possible interferences.
Paul2748, Nice catch on the rocker arms. Maybe they were changed to accommodate the pistons?
DryLakesRacer, I had not thought about the 292 being a lower compression. Was that due to the heads, pistons, or stroke? Just wondering if the ECZ-G heads would have raised the compression or were they also used on the 292 when stock?

Sorry if my questions seem trivial, but I'm still on a steep learning curve. 


 

You really want to establish the static and dynamic ratios. Not to mention valve to piston clearances. My first y block, back in 1967 was a 40 over 312, with “11.25” Jahns pistons. Pro built engine by a guy in AA fuel for his roommate in a 55 bird. That’s a whole story in itself. That car would only run on scrubron “Custom Supreme” advertised as 105 octane minimum.

When I put the aluminum heads on my 9:1 static 40 over 292 stoker the static went to 10.7x to 1. We spent a long time picking the cam specs (thanks to Ted Eaton and John Mummert) to ge the dynamic down to 8.7 IIRC. It’s still very marginal on today’s pump gas.

Doing it over, I’d have cut or changed the pistons. So take your time to figure it all out and do it right. Just go price racing fuel, that will get you motivated.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks for this and I am really trying to get to a good street motor that will not need a lot of care and feeding. To that end, replacing the pistons is certainly an option on the table, and I realize there would probably need to be other changes as a result of a piston change. A different cam and rockers may be in the final recipe. Characterizing what I have now is the first step. I have the time to get it right, but need to understand what right is. 

Thanks again to everyone sharing their knowledge. It is very much appreciated

While the G head is often referred to as the 312 head, it was the standard cylinder head on the 1957 Ford 272, 292, and both the D and E code 312 engines.  It was also available on the 1957 Mercury 312 engines.  That helps to explain why there are so many G heads floating around.
 
The nominal advertised combustion chamber volume for the G head was 69cc meaning that in a best case scenario, the combustion chambers would be as low as 69cc.  On stock and unmodified heads, it’s not unusual for them to be larger than that as 69cc was the minimum size for those heads.  Until the heads are measured, it’s questionable as to what the actual combustion chamber volumes are.  For the G heads, the amount to mill them for a 1 cc reduction is 0.0064”.
 
There are both small letter and big letter G heads.  All the small letter G heads are unposted.  The big letter G heads cast at the Cleveland foundry after May 1957 are posted while those being cast at the Dearborn facility remained as unposted until the end of G head production at Dearborn.  The service manual was adamant in not milling the unposted heads any more than 0.010”.  The posted heads have been known to be milled as much as 0.065” and not have head gasket sealing issues even with increases in compression ratio.  Here’s the link on how to identify posted G heads.
http://forums.y-blocksforever.com/FindPost6764.aspx 

Lorena, Texas (South of Waco)

I see grade six head bolts in one of your pictures.  It would be a good idea to change those out to grade eight head bolts when the time comes.
 
Without more specifics on your engine, here is a rough guess as to the compression ratio.  Once you know the actual dome volume, deck heights, combustion chamber volume, and some of the camshaft specs, these numbers can be fine tuned to get the real compression ratio.  As it stands right now, the domed pistons does have the SCR back in the neighborhood of where it needs to be for a healthy street engine.

Lorena, Texas (South of Waco)