first tell us why??? are you raising the X? going from trs to bravo?? erc...

Raising the X of the drive for better performance and less drag hopefully !

Do yourself a favor and pick up a -2" lower. Simply bolt it on and add fluids.

Trace the lower 2/3 of the cut out, laminate two pieces of 3/4 ply together and trim to fit. Glue it in then grind back about 5-6 inches feathering the edges, then start laying layers of 1708 and ve intill it's built up on the inside and outside then make sure it's flat,. Same with the exhaust holes as they are going up too ( though you don't need to feather out a far)

"MerCruiser OEM transom adaptor kit for use when replacing a Volvo Penta, Cobra or BMW sterndrive fitted with a standard MerCruiser Alpha or Bravo sterndrive assembly. This kit provides a rugged mounting support that seals the competitors' larger transom cut-outs and eliminates costly rework to fiberglass, aluminum, or steel transoms. Much easier than filling in the transom, re-glassing and re-cutting."
https://www.mercruiserparts.com/8276...plate-kit-tran

You didnt say that.. my way works for bravos as the area being filled is small and the new cutout overlaps a lot of the area....