According to Wallace a WF engine could be one of 4 engines:
Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc 1965 389 338 HP WF M 10.75 066 77 / 9778777 3-2 (F)7025178 (C)7025175 (R)7025179 Block Casting # 9778789 Should have full head production number under valve cover - 9778777 1967 400 350 HP WF A 10.5 066 670 1-4 4242S GP A/C Block Casting # 9786133 1969 428 370 HP WF M 10.5 067 62 1-4 7029263 GP Block Casting # 9792968 1973 350 150/175 HP WF A * 7.6 555 46 1-2 7043062/63/72 Block Casting # 488986; * shows auto in service manual?