[FWB]

if i read that correctly it's a "P" coded block? i would not let the service block stigma stand in the way of your decision. it will probably outlast you.....
some say the service blocks coded "P" were more desirable. i don't have any insight to back that up....but if you consider these cars are a fair weather vehicles and usually don't get driven a whole heck of a lot of miles. if there is good documentation of the build and its a solid build it will be fine. remember it is a replica, the service block will put out the same HP any other block will.

could it be a marine block? is there a machining mark thru the bulge of the side galleys?