ok, usually there is torque, current and voltage details on the plates.
Hood

Ok got the spec sheets and the motor.

Moog D315-007B  Brushless DC Servomotor (Resolver with IP65 housing)
Cont Stall Torque:  5.5 Nm, 48.675 in lbs, 4 ft lbs
Continuous Stall Current:  12.4 A
Peak Torque:  16 Nm
Nominal Speed: 4900 Rpm
Terminal Resistance:  0.88 ohms

Here is the Duty Cycle graph and graph legend as attachments.  The current motor is a 3 phase 208 2hp 2500Rpm Chinojunk special, so this Moog will pull the teeth out of the AC motor at any RPM, and has a top end RPM that's almost double the speed.  What's left is:

Deciding whether to mount an encoder (mounting will be difficult, and I'm worried about slop in the gear head, so I'm thinking I might need the encoder on the spindle itself), or go with some kind of Resolver to encoder converter board;
Sourcing a drive that will do 310VDC at 15 amps peak and 5.5 amps continous;
Finding a power supply.

Recommendations?

David

I think you may struggle to find a suitable drive for that, I know brushless DC motors and AC Servos are very similar so possibly one of the drives I use would work, they are Allen Bradley DSD- HV drives. You would need 220-460v three phase but if you just had 220 then that would limit your voltage output from the drive to 220v which in turn would cut the max speed of the motor.
As to the encoder, can you not remove the resolver and fit the encoder in its place? Also a lot of the Yaskawa drives for AC Servos can accept resolver input but again not sure if they would be suitable for a DC Brushless. One other thing to note is a lot of industrial drives will either have models that accept Step/Dir or Analogue so be carefull if you find any on eBay and make sure you read the specs. The Allen Bradleys that I use can accept either.
Hood