340rocker oiling

Was the engine rebuilt? I put a generous chamfer on the backside of the cam bearings where the oil hole up to the head is because I noticed a lot of blocks the holes don't completely line up. It may be the cam bearings are partially obstructing the passage. The only way to "know" is to either pull the head and try to flash a light down the hole or (preferred) pull the heads and cam and flash a light through the cam bores while you look from the deck surface down the hole.