Big D:

The first pictures you posted were from about 1987 or 1998, with the K&B carb and direct needle mounting. If it had the remote needle then the date would in the early 90s to current. The later post shows the same type 4011 engine in an earlier version, around the early to mid 80s, with the Perry carb.

All your illustrations are the type 4011, which is a current engine, and except for carb differences they are all the same.

Bill.