I don't think it costs $50 to replace the dial gauge with a jiggler

$16.99 + $5.95 S&H = $22.94

May you also need a new vent pipe , +$7.99, for total of $30.93

http://www.yelp.com/biz/technical-services-group-alameda these guys might do testing,
but dial gauges seems like a hassle to me

The presto canner manual gives canning times for meat for 15PSI ... I can't really tell how much pork you're canning , but all I can say is overcooked meat is tastier than poison meat