Hmmmm -- excellent question! Maybe. How do we tell T from F?
I believe there will be a T or F cast in the block to ID the engine foundry...maybe some of the members with open blocks can look them over...it may be on the inside by the crank.
And while we're at it, here's a later 261 (with Captain's Bars) -- what is the clock face looking mark in the date code and what is it telling us?
The cast clock indicates the 10 hour shift, 10 dots in a circle with the dot outside the circle and a pointer which indicating the time of day and shift (I forget which is which). It was another way to help isolate problems in the casting process.
Mike B
