Excellent advise from Hotrod Lincoln. I just want to add a note. Several years back the engine in my 38 Chevy was stuck. Instead of buying and the waiting the shippng time for a penetrating oil product, I took the advise of an older friend. (I am near 61 and have been twisting wrenches since age 15)
Mix 1 quart of Dexron transmission fluid and 1 pint of DOT3 brake fluid. Follow Hotrod Lincolns advise by waiting a week (pour some of this mix on the valvetrain) and then grab the crowbar. Do not try to spin the flywheel, but gently try to move it in 1/4 inch increments. Once you are able to move the flywheel 2 or 3 full revolutions, you should be able to now rotate it by the harmonic balance and fan belt. Have a friend watch the valvetrain to avoid any binding. If you have success FIRE THE SUCKER UP.... Brake fluid will snatch the paint off your fender, so it will also cut dissolve the varnish build up. Dexron has rust fighting and detergent additives. Look at the inside of an automatic transmission (used) and note how clean the internals really are.
A good friend, who has built quite a few streetrod motors, uses 4 quarts of Castrol and 1 quart of Dexron for engine breakin period.
I actually drove my 38 around town off and on for several weeks before changing the oil. I don't recommend this to anyone, even though I had no problems. Have Fun, SportTruck
