Nick, Below is a screenshot from the
1954 Chevrolet Truck Data PDF that gives the breakdown on your engine serial number. Chevy used the I (as in India) for the numeral 1 in serial numbers. Hope this provides some help with your question.

0022139 = the engine unit sequence number from the assembly line for that year (all serial #s began with the number 0001001)
F = Flint Assembly Plant
54 = 1954 model year
Y = Passenger car equipped with a Powerglide transmission
NOTE: Powerglide equipped engines came standard with hydraulic cam/lifters. If your engine has a solid lifters it has been converted from the original equipment.