CAM AND MAIN BEARINGS SHOT

I left something out...
the oil pumps relief valve could have been stuck open from debris ,delivering low pressure 'as low as 20 psi even at say..5000 rpm...and that idiot light won't turn on till it gets below 12 or 8 psi iirr...so you wouldn't know you were starved for oil...now couple that with mis aligned oil passages at the main bearings...and the bleed off else where like at the no.1 cam.