29-09-2018, 03:41 PM
I find the simplest way to match the ports is to make a stiff paper gasket. Punch at least two holes to neatly locate it in position on studs then rub the outline of the ports. These can then be carefully cut out and the gasket transferred to the other side for comparison, keeping the right orientation of course. Mark with a felt tip where it needs work. I've tried other ways (blueing, spray paint through the port etc) but found this works most reliably. You can be as fussy as you like but the returns diminish.