If your talking about priming the oil system it depends on how the oil pump is driven. Add coolant to bring coolant level up when the air locks circulate to radiator.

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How to prime engine after rebuild. Refer to valve lash procedure and lash valves. If oil pump is crankshaft driven you use a pressurized container to move the oil ties in where the oil sending unit is located. The engine should be allowed to run at normal operating temperature. How do i prime the engine after rebuilding 31. Stone simple and free way to prime the oil pump and make sure you have oil pressure on a new engine. Run the engine between 2000 and 2500 rpm with no load for first 30 minutes.
If distributor driven with distributor removed you can use long tool to reach down in there to drive the oil pump. It is a good idea to leave your radiator cap off until your thermostat opens and water starts to circulate. Works on any engine. Adjust the distributor timing to recommended specifications. Before starting your rebuilt engine for the first time be sure it is pressure lubricated. This means priming the oil pump by turning engine over with starter without spark plugs.
Never add cold water to the cooling system while the engine is running. Start the engine and bring rpm up to 1200 1300 rpm until water temperature just begins to rise. Be sure to check the oil level in the engine and prime the oil system.