9 bolt iron heads ?

[flthead]

have a couple 9 bolt cast iron heads for the big twin flatheads , some with the primer screw plug in them ,some without . anybody know the correct years for heads without the plug and with the plug

[vride5]

i've always thought the ones that were tapped were for the 36 V models an the ones not tapped were on the early U models
Dave

[Steve Slocombe]

Early UL 9-bolt heads had the tapped holes filled with blanking plugs rather than the primer cups used on the 1936 VL. It looks like the new head casting with the smoothed off place, where the primer cups were, was introduced as a running change in 1938/9, but this is a guess. 1936 front heads can be distinguished because they do not have the dogleg in the fin to clear the 1602-37 spark plug cable bracket.