You might be able to borrow, if not buy a fuel pressure tester gauge from a local auto parts. I am not sure what spec is on these, but from past experience, 30+ is good, under 15 is bad. Some older cars were in the 50PSI or higher range. When it is running and you go full throttle, does it feel weak on power?
Something like this
http://www.matcotools.com/ProductImages/FIT450.jpg
simple to use.