Old Balancer outer rings slip. Need to zero degree your timing marks to be sure. And there are 2 different timing covers with zero at 2 o'clock or 11 o'clock (IIRC).
Temp? RPM?

JOE
II# 3486
'48 FLEETLINE AERO

http://s639.photobucket.com/albums/uu117/lars62go/