Balance issues

Duster 72 said

Its a 77 block 440 bored 30 over 10.1 compression cast crank they didn't supply any paper work besides build. Full engine break in. Factory crank they turned .10 bearings were right size just never seen before. Found cotter pins in oil pan they assembled 100% of motor minus carb

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I guessed wrong.
Do you have any pictures? Is the tip broke off the intermediate shaft? If not, stick it in the oil pump and see if you can spin the pump.
Did you prime the oil system before startup? What was oil pressure during priming and while it was running?
Were the cotter pins you found damaged, like they got into something in the engine?