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i picked up a 1947 chevy p/u 3100 series this truck last ran in 1972 its been garaged since I cant free this engine up to turn over is there anyone that can give me advice without having to break the motor down

It may be stuck to where you have to tear it down, but taking the spark plugs out and squirting Marvel Mystery Oil in each hole and let it set for several weeks might help. To turn it I would take the tin cover off the flywheel housing, use a pry bar on the flywheel ring gear to try to turn the starter ring gear. Try it both ways. Sometimes you can get them to move a little one way and then a little the other way until you can get a complete revolution. If this doesn't work, taking the head off and using a wood 2x4 as a punch, hit it with a hammer. If this doesn't free it up, you probably will need a total overhaul.

Sometimes there can be something other than the pistons that are frozen. A couple of years ago I started to take apart a 261 that had been in "storage" (twenty years outside under a tarp, then 22 years in a garage) for 42 years. A little WD-40 loosened the pistons, but the camshaft bearings were frozen and the crank would only rotate within the backlash of the timing gears. I made a tool to apply torque to the cam (with the crankshaft gear removed), and after a couple of weeks of penetrating oil and torque application, the cam finally broke loose. I have also seen oil pumps freeze up.

Dave1947: WElcome to the bolt.

This topic has been discussed many times. It will depend a lot on just how bad yours is stuck and you will probably not know that right away.
Fist understand that soaking it "overnite" may not do the trick. There are some that takes a while to penetrate which again dependd on just how bad it is.
Many ways have been tried and to some degree they all have worked one time or another.
Disel fuel, Marvel Mystery Oil, WD-40, Kroil and automatic tranny fluid just to mention a few. Soak it, try to turn it, soak it and repeat. Using the pry bar on the on flywheel teeth is a good idea. Be patient. Give the stuff time to work and save yourself from tearing up stuff.

Be very careful with the fly-wheel and prying. The teeth can break off. Use a very large broad tipped bladed screw driver and wear safety glasses!

The one time I dealt with a stuck motor... I pulled the plugs and squirted automatic transmission fluid in the holes. After setting for a couple of days I rocked the truck back and forth in the top gear. When the ATF came squrting out of the spark plug holes, I knew it was free. Mine wasn't stuck too bad.