I want to replace some of the ports on my '83 H30. I am measuring flange size of 15 1/2 x 7 3/4 but see listing in various souces of 7 3/4 x 14 5/8. Will these work or is there a lot of filling to do? Will the screw holes fit?? I am looking at Becksom. Wahat were the original mfg on the hunter? What is the best replacement if not replacing all?