Basic engine used in Ford and Mercury passenger cars and trucks that can be interchanged:
CDI Casting # PASSENGER CAR/TRUCK    
292 EDB 55 thru 62 Ford/Merc    
292 ECK 55 Police Interceptor    
312 ECZ 56/57/58/59 Ford/Merc    
272 ECG 55/56/57 Ford/Merc    
         
The 272 is essentially the same engine as the 292 but has a 1/8" smaller bore (3.625). There is a lot of meat in the block and it can safetly be bored .125 oversize to a standard 292 bore (3.750)
         
The 292 can be safely bored .060 oversize. Keep in mind that a 292 bored .050 over, gives you the standard 312 bore (3.800), but with a .14 shorter stroke (3.30 for 292, and 3.44 for the 312).
         
The safe bore limit for a 312 is .040 over. A 312 bored .040 will give you a 319.5 CID engine. It is not recommended to bore past past .040 because of wall thickness.
         
Ford, as usual, was not 100% consistant in the use of engine identificaiton markings, as you will notice in the chart below. However, in most cases these markings are adequate to identify which engine you may be looking at. If the engine is in the vehicle, you can pull the bell housing/flywheel inspection plate, and sue a flashlight to check the markings on the crankshaft flange ( refer to chart below)
         
Engine Year Marking Location I.D Marking Description  
312 56/7/8/9 L.H. side between oil filter & head (Usually) Raised casting letters ECZ  
312 56/7/8/9 Crankshaft rear flange A half moon on one side. A flat with 1 large dot on the other side.  
292 Mid 50'S L.H. side between oil filter & head Raised casting letters ECK  
292 Mid 50'S L.H. side, lower front Cover over vent hole  
292 Late 50's L.H. side between oil filter & head. Also center rear next to distributor Raised casting letters EDB  
292 Late 50's L.H. side, lower front Cast over vent hole  
292 Early 60's L.H. side between oil filter & head Raised casting letters C2AE  
292 Some L.H. side between oil filter & head Raised casting letters ECZ  
292 55 to 62 Crankshaft rear flange A half moon on one side. Flat on other side. No dot.  
292 55 to 62 Crankshaft rear flange 2 half moons.  
292 55 to 62 Crankshaft rear flange A half moon on one side. Flat on other side. 2 or 3 small dots.  
272 5/6/7 L.H side, between oil filter & head Raised casting letters ECG  
272 5/6/7 Crankshaft rear flange A half moon on one side. Flat on other side. 2 or 3 small dots.  
272 5/6/7 Crankshaft rear flange