Propeller bolt upgrade
I have the same engine , and at over haul , before installation,I had the shop put new flanges in the hub so I could install the Sensenich prop that had 7/16 bolts . As suggested if you intend to use a prop that will be using 7/16 bolts , that?s what needs to be done. When I contacted Lycoming and Sensenich they offered no other solution , apart from change over of prop or engine. I should say I haven?t flown the combination yet , but I?m not expecting any issue. Good luck.