Technical Possible lifter tap, please help.

I have a 1940 Chevy 4 door sedan. I installed a 235 6 cylinder from a 1957 Chevy car. The engine sounded really good before it was removed from the car. I then installed the engine in my car. The engine ran really good in my car. Then I got busy with other things and parked the car in the barn. The car sat for about 4-5 months. Today I started the car and there is a tapping noise coming from under the valve cover. What could be wrong and what can I do to fix it?
Thanks




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Give it some time to heat up and give it a few miles of drive time. Stuck lifters are not uncommon, just be sure the rockers are getting oil.

 

Could try the classic remedy - replace 1 quart of crankcase oil with 1 quart of that marvelous mysterious oil.

 

Maybe pull the rocker cover to verify all 12 valves go up & down. We have trouble with today's fuel causing things to stick.