Listed as "crank forging" #'s.
1939-52 had Dome Pistons, 5/8"
Block casting # for the 228 CI is 6107326.
Block casting # for the 248 CI is 6107328.
Both used crank forging # 6107342 or 2191127.
Both used head casting # 2136477 or 6107412.
1953 -248 CI had Flat Pistons. Same block, same crank forging #, head casting # 2194819.