The 1966 is a stock 1300 cc motor, US spec. stoc cooling system, narrow fan.
my other bug is a 1600 Dual Port with wide fan, offset oil cooler.
The bottle of Delvac 1300 says.....
Meets or exceeds the requirements of CJ-4, CI-4 PLUS, CI-4, CH-4, SM,SL.
So bottle says it meets SM standard...