Identification of 223?

I recently bought a 223 that the seller claimed was from 1954. It isn't. From discussions on the Ford Truck Enthusiasts board I've narrowed it down to 1957-1960 with 1960 being the most likely year of manufacture. Here are some pictures of the 223. Are there any casting marks or numbers that would narrow down the year? The only casting mark I found tells me it's a 223 which I already know. Any help would be appreciated!

Thanks!

I posted casting numbers on my web site: 223 info

My block is EBP-L with 7/16" head bolts. It has a valve cover with mounting bolts around the perimeter to the head instead of through the top to the rocker arm. It also has "Ford" stamped in the top of the valve cover which I'm told started in 1960. So, based on all this information I have concluded that the engine was built in 1960.