Hello Jean, to replace some, not all your vacuum ports you will have to 1) be sure the industry standard ones fit your backing plate behind the faceplate. Read the text at the top of this page for that http://builtinvacuum.com/inlets/basic.html
. And 2) you will will have to put a new end on your vacuum hose. Cut the end of your hose off or pull your end off. Reverse thread this new end on the hose and you will be able to use it in the single and dual trigger point inlet valves http://builtinvacuum.com/retail/shopretail.php?part_no=302HCR
. We are assuming with this that the diameter of the inlets you do have is about 1.5 inches, not 1.25 inches.