Frank,
I know, but starting Jan of this year production is restricted and I guess availability and cost will be impacted. The 417a is supposed to be a drop in replacement and more friendly, so why not.
Sounds like a good fit. Check for compatibility issues with your metering device (they are not all created equal). I'd take the time to do an oil test to make sure there are no impurties, pull a very good vacuum (400 mic) and go for a recharge.