I would tell you that you are headed for trouble. That pump is so oversized for espresso machine use that you may very well NOT be able to tune it down. A short visit to the Procon website will reveal a lot: http://www.proconpumps.com/index.htm
I am not too familiar with Procon code numbers but the most common Fluid-O-Tech pump used for our espresso machines is a model No. 054. My suggestion would be to contact these guys: http://www.jcbeverage.com/index.html
and see if they have a motor pump combo you can trade in on with the idea being to get the Procon equivalent to the Fluid-O-Tech 054 or, for that matter, a motor and rebuilt FOT 054.
Your intermittent vibe pump problems may very well be a slightly maladjusted brew switch.