I'd like ta get some help finding out if I have a #s matching engine in my 55 crown vic. I was told I needed to make sure what I have before making any mods. Im sure somewhere here somebody has already answered these questions. Are there on-line sights that decode engine #s? And where will I find these #s? And are the blocks all the same through all the engine sizes, 272, 292, 312? It seems from what I've read here, that the heads and cranks are what makes the difference. Are the heads marked for each different engine size? I know this sounds like a lot of questions, but I am a newbie to the y block. I will appreciate any help/info that I can get on this - RL - and Crown Vics Forever!

Rowen
55CV
Woodland, Ca

Casting numbers off of the block and heads are a starting point.  There is also a date code on the block that should  precede the production date on the VIN plate.  The same holds true for the date codes on the heads which can be either on the exhaust side of the head or within the valve cover area depending upon the head itself.  On the right front of the engine (looking from the front) just ahead of the valley cover is a stamped number that gives some additional information regarding when the engine itself was assembled. 

Lorena, Texas (South of Waco)