Fan patterns: The "small" pattern was also used on the Mouse (SBC). So it was on both the I6 and the SBC. I don't know what year they switched over to the later big pattern, maybe the same year they switched from the Rochester B carb to Satan's Carb (the Monojet:).
The "Small" pattern is also the same as the Ford fan, I have used 4-blade Ford fans on the 250 and 292, with the right water pump there is enough clearance to the rad. I did have to space the fan out maybe 1/4" to clear the double-pulley 292 damper.
