351 Windsor motor

Take the spark plugs out and try to turn it over with a wrench or socket. A squirt of oil down each spark plug hole is a good idea.

If it has the starter motor you could try to turn it over with jumper cables.

The motor is out of the truck right now sitting in the garage. Bought it from a salvage yard to replace the old one. Trying to figure out how to check the bought one as was told it to was seized up. Already put oil in the one cylinder that didn't have a plug in it and has been sitting for a week since did this.

Since this is your motor spray penetrating oil in each cylinder and let it sit over night. Good luck!