Found on another FORD site:
The C7ME casting ID on the block outer wall molds appears on 352, 360, 390, 410 and 428 blocks in Ford, Mercury and Ford light truck FE applications.
It has no particular significance except that it means you have a 1967 model year or later block.
The C7ME marking was only used for a year or two, pretty much gone by the end of '69 model year.
If it IS a side oiler 427 block.....
2020 Ford Ranger STX DFI Turbo 2.3L 10 speed Auto
2017 Ford Fusion Sport DFI Twin Turbo 2.7L V6 6 speed Auto (14.000 ET bone stock in 82 degree heat)
1985 Mustang GT 5.0 Hatchback 4bbl 5 speed manual (525 HP 363 Dart block/AFR heads with Magnum 6 speed in the works)
1984 Mustang GT 2.3 Turbo Convertible FI. 5 speed manual
1966 427 Cobra (ERA) 468 all Aluminum FE 2x4bbl 5 speed manual
SOLD : 2003 Mercury Marauder FI. 4 speed Auto
w/Crower Cams & Springs, +1mm SS valves, mild port job on the cylinder heads.
Extrude honed intake w/PHP spacer.
Kooks Headers w/2.5" High Flow Cats & X-Pipe, Magnaflow mufflers, OEM tailpipes w/Megs Tips
B&M Trans cooler w/fan, Level 10 Shift Kit, Art Carr Hughes Deep Sump Trans Pan,
SVO Rearend Girdle, Redline Gear lube; OEM 3.55s
'Real Gauges' + matching Trans Temp, Oil Temp, Water Temp, Fuel Pressure, Vacuum/Boost Gauge
Built: 10/15/02 Bought: 12/16/02 Sold: 10/15/18