[FFR428]

Hmmmmm. I've had a few 428 service blocks but not a 427. One of the 428's had the same sort of date code as your 427 and the other two dots under a 2 at the beginning and neither had casting numbers. From what I've found the dots were for a 70's block and the number over them the year cast which made it a 72 block. It had a CZAE-6010-F part number on the Ford box and was a 428 service block with the external ribs. I never did figure out the other but have it jotted down in my notes somewhere. Your looks like a Nov 4 1972 but who knows. One of my blocks had part of the date code ground off and had to use a lupe to see it better to figure it out. Service blocks have always been kind of a mystery block to some myself included. I continue to find bits and pieces of info on service blocks and find them very interesting to research. I love a good puzzle. G.