block markings

Poking around the rear flange (near trans), I found a 10 dot dial with an arrow in the middle and another dot outside the circle. Obviously some sort of chronological marking. Does anyone know how to read this clock? The arrow is pointing between the 2 and 3 if the outside dot signifies the top of the dial. It's a smallblock from the Flint plant.

JR

JR,

That is a shift clock.

It tells which our of the shift that the part was cast.

The outside dot represents the start of the shift, and the indicator points to the number of hours into the shift when the part was cast.

This "clock" can be found on the block, intake, heads, etc.

Anthony

Thanks, Anthony!  Interesting how they even narrow it down to hours of the day.

JR

JR,

The guy who is rebuilding my engine told me that there was a  belief that blocks cast in the earlier part of the shift had a higher nickel content in the cast iron than later blocks.

This made the earlier blocks more desireable to race teams.

I have no idea of this is true or not, but I bet that superstitious teams felt better if they got an early block.

Anthony

Hopefully, that might offset the fact it rolled off the assembly line on a Monday

Thanks for the factoid(myth?), Anthony.

JR