Bob. This HF worm gear winch could easily get transformed into an rotator for $35. The winch is rated at 2000# so it ought to turn a 700 # engine over/
https://www.harborfreight.com/2000-l...nch-63755.html
Just a little welding and fabbing, you'll have yourself a manual rotator engine stand.
Link to how one guy fabbed up his homemade rotator:
https://www.hotrodders.com/threads/m...otator.523367/
Hit the (see more) tab above the first photo to see all the pictures, and steps.