Jeffrey,
Here are locations and names for various casting codes.L 4 7 looks like a block date casting code - check the location at the link above.
L = 12 = December
4 = 4th
7 = 1947
F 207 B
Flint, Michigan assembly plant
2 = February
07 = 7th
B = 235 car engine with Powerglide transmission (it would have had hydraulic lifters)
Those head codes are not the pertinent codes for identification.
Perhaps it is a very late 1947 engine that had been installed in an early 1958 vehicle?
