Hello,
I have a stumper. 76' 500" motor rebuilt 17 years ago and stored since. Some lube in cylinders but never any coolant since rebuild. The engine is from RWD but pan/sump are from Eldo. I recently put the engine in a vehicle, and to wake it up, I pulled the intake and rocker covers, slathered the top end and cam with assembly lube, and lubed the cylinders with Brad Penn 30w break-in oil. Put that in the sump, filled the new oil filter with it, and packed the oil pump. Then spun the oil pump. My electric oil pressure gauge wasn't wired in for view, but I had oil bubbling out the sender drilling at the back of the motor. Each cylinder ran 215 psi within 5%. Added water. Started engine. No oil pressure on gauge, but oil definitely getting to sender. But the oil was now foam green..... Engine shut off within 3 minutes. rpm was 1200 when running. No bad noises. Inspected rockers....lube still in place. Plugs all dry. Retorqued heads....minimal change, maybe 100 before torquing. Coolant pressure test done with distributor out and oil drained and sump plug out and intake manifold off. Water/oil shoot out of lifters with pushrods removed. Both sides. Inspected timing chest. No apparent cracks. Compressed air into sender passage at back of engine also sends water/oil/air out of lifters on both sides. Huh?? Internal crack somewhere near front of engine? Resigned to finding another block, but have you ever heard of this?

 

lesson learned....don't plumb in your heater hose using the 3/8" plug access above the oil pump. It is an oil galley.