engine code

Was wondering if there is any way of telling what year the engine is by reading the engine code on the side of the block just in front of the distributor. My code reads 209MXI6 the po said he did replace the motor a few years back but does not remember what year XJ the motor came from.
Anyone who may have the code breaking abilities it would be greatly appreciated. I have a 1988 Wagoneer LTD. 4.0L, AW4, 242 tc thank's very much for any and all your help

Look on the drivers side for the casting number. The code by the distributor is the build date of the engine.

4.0 L Block Casting Numbers located on the driver side of the block just above the motor mount and below the frost plug.

Year............Casting No
1987-90......53005535 (8933002665)
1991-95......53008405
1996-98......53020569
1999-04......53010449


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Kick a$$ man great pic with the info much thank's turns out the po did replace the motor in my waggy at some point. I have the 53008405 so does this mean if I was to buy a long block I should look for a 91 to 95 4.0 ? and is this actually a H.O. motor? Again thank's this clears up my doubts he ever did a motor swap.

1991 is the start of HO motors. Any XJ or ZJ 4.0 L should fit, (do your research) but 91-95 has no worries about the belt driven pulleys and accessories bolting right up.