Opinions on these Reliance 0690 servo motors for BP conversion

As is a poster a few posts below, I'm looking seriously at these
Reliance servo motors for use in a Bridgeport clone conversion.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7511611969

They have the following integral encoder:

Integral Encoder: Agilent P/N HEDS 5605#A06

500 Line yielding 2000 Counts/Rev.

The motors have a nominal voltage rating of 120 volts at 4 amps
continuous. The seller claims they will work fine with a Gecko drive
at 80 volts. The coders are 500 lines, yielding 2000 counts per
revolution.

The seller also claims these are big enough for a BP conversion.

Will these motors have enough power for a Bridgeport conversion, and
is the encoder count correct for this? The fact that the are Nema 34
size instead of the Nema 41 size more commonly used on BP's is
making me nervous.

I originally was planning to use stepper motors as I thought servos
would be too expensive, but if these will work I'll go servo.

Thanks,

Paul T.