That slight cutting was also a standard Ford practice (there is a dealer cutter kit even) since 59 type blocks eventually became the replacement block for the prewar engines with the different valve angle.
Heads that fit...any of the several variants of 59 numbered heads, Canadian or American. Buy in pairs as there are two or three minor compression variants. Also Canadian C7RA heads, the 1947 replacement for the C69. These came in iron and aluminum variants, with the aluminum one about a point higher in compression.