427 Side Oiler Production Date near oil filter

[GT500#1493]

Need some help in possibly identifying the production date of my engine. I know the engine was installed in my Shelby Mustang in 1979. What happened to the original 428 is unknown other than the owner wanted more horsepower than stock. I’ve taken a photo of the pad adjacent to the oil filter on the driver side but having difficulty in deciphering that one digit to the left of the H. Any help would be appreciated. The heads are iron and the lifters are solid, not hydraulic.

[ERA174]

The following link has information that may be helpful to you.
https://www.diyford.com/how-to-ident...ord-big-block/

[jetblue69]

The H10 would be the 10th day of August of that year. But it sounds like you already figured that out...

There should be another casting number with a "C" or a "D" i.e. C5AE-H above the machined filter housing face.

Unfortunately, even if you had that you still would have to look at the guts to see what it really is.

[FFR428]

First digit looks like a 2. In 69 Ford put dots under the first number of the date code. To tell 59 from 69 etc....Very common to see. 2H10 = 72/Aug/10.