Hi Rod
Probably no difference between Pat 11 & 12, but there are differences between Pat 12 and 13.
Here are a couple I've noted:
- Length of cross shaft
- Drivers side lever arm is different length.
But these differences are pretty self evident when fabricating. Trying to this with the nose sheet metal in place is very difficult but with the radiator remove and nose removed on Pattern 13 removed or the center sheet metal panels on the Pat 12 off it isn't bad.
Cheers Phil