Cold Starting Long Standing Engines

I would also suggest you change the oil if the pan is currently filled to remove any condensation that may have accumulated in the oil and pan.

Another check is to ensure the lifters are rotating i their bores before you fire it up.

If this is the first time it will be fired up after a rebuild use a quality break in oil or oil additive win sufficient zinc for the flat tappet cam and lifters. You also want to ensure the engine fires up quickly and get the rpm’s up to ~ 2000 rpm for the cam and lifter break in. There are many threads on here how to go about getting ready for the initial fire up including getting the timing lined up, a known carb and the carb full of gas, ....