If you're talking about that 1/4" diameter hole just ahead of the big hole for the draft tube, it's for attaching a baffle inside the crankcase that prevents the crankshaft from throwing oil up into the road draft tube as it spins. Look closer- - I think -there are actually two of those holes, but I might be mistaken. The sheet metal baffle goes across under the road draft tube and deflects the oil that's thrown off the crank. Leave the baffle out, and the draft tube will pee oil like it's on Lasix!

Edit: forget the second hole- - -I was thinking about the two headless bolts that hold the oil pump adapter to the block under the distributor hole!
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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