Where to get a front pump for a 42RH (A500)

Okay, thanks for all the info. I'll have to dig around and see if I have access to any gauges that will go that high. Pretty sure most of the stuff I have laying around maxes at 80 or so. Maybe I can get a loaner from the parts store or something. Nice to see there are easy ports to access though, should make it fairly straightforward to check.