i counted the bolts on my valve covers on my car today... i have 11 bolt valve cover, probably meaning i have a Romeo block. when was the 11 bolt romeo block put into the Mustang? and when was the Windsor block put into the mustang? and to add some information, the front cover bolts on my block are 13 millimeter.

EDIT: and where would i find the casting code on the block, so i can make sure my engine didn't come from, say, a 2001 or newer car with a XR3E casting code block?

 

In 99 and 00 the engines were made in windsor before and after that in was romeo