Thanks everyone for the information.
A local engineering Co. has inspected and measured shafts and gears and can handle replacement by manufacturing if / when required.
Spectre, This machine has been modified and has helical gears and is rated at 30m/s (5400f/m)at its last installation, refurbished 6 months before shutdown.
Thanks again to everyone who had input it was very helpful.
In 1972 we knew that helical gears would be lots better and quieter but delivery time and cost in addition to the cost of replacing the motor made the helical gears the odd man out. We were able to double the speed from about 2,100 to 4,000 fpm which was pretty much the limitation of the spur gears.