No oil pressure after oil pump installed
No, that would go the other way, more pressure due to closed oil galley holes. You would know it if you had spin a bearing. Did you prime the pump with something like STP or Power Punch before you put it on? If not that is most likely your problem.
I agree with tennisshoes on his method, oil pump needs to be primed, but if the engine is already installed, you can do it when it is installed which is how I do it, by rigging up a rod on a drill to the oil pump shaft and spinning it until oil has circulates threw the engine.
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