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340...L2316-30. xe-268, x heads,
stock fan shroud,new clutch fan,
12 initial,35 tot all in at 2400, 49 tot. w/vac advance and will ping about twice when i get on it w 91 octane
i tried E-10, 94 octane and it detonated badly ... makes me think lean.
compression is probably borderline for iron heads



49 degree total advance, sounds a bit much. Disconnect vacuum and drive it around see if that helps.