Bill - It took some fairly deep diving through various GM resources to decode your stampings on the block. Primarily because in 1972 and similar years the Chevrolet in line 6 cylinder was the GM Corporate engine for various GM lines including Chevrolet, GMC, and Pontiac.
If I've done my work correctly
your first line on the block "F0142Y6" decodes as:
F = Flint engine assembly plant
01 = January (assembly month)
4 = 4th day of the assembly month
2 = 1972 model year
Y6 = Pontiac 250 w/1 barrel carb and no specified transmissions (used for both automatic and manual transmission equipped cars)*
The second line of your serial number info "22P194474" decodes as:
2 = GM Pontiac Division
2 = 1972 model year
P = Pontiac, MI vehicle assembly plant
194474 = last 6 digits of the Pontiac car assigned VIN this engine was installed into
Since this is a GM "Corporate" 250, you should be able to use Chevrolet Shop manuals to cover maintenance/repairs and overhaul as well as Chevy listed GM part numbers and engine identification for ordering parts. It might be a good idea to compare timing and related specs between 1972 passenger car and truck 250's as there may be a difference enough to warrant using the passenger car info for best tune ups and operation settings/adjustments.
* The "Y6" code came from this
Pontiac Engine Decoder pdf I found on line in my search.
Think this covers your question.
EDIT NOTE: A check of
1972 Pontiac vehicles that came equipped with 250's included the base level models of the Firebird, Lemans, and Ventura II (corporate copy of a Chevy Nova).
