"X" dimension on Early Executioner

OK it's not a Fountain, but the bottom on my 1984 Excalibur 31 is the same as the first Fountain Executioners.
Pad Bottom, Notched Transom.

I converting my Merc trans and TRS drive boat over to Bravos
New transom is being installed this week.
Leaving the engine at the same height would move the prop shaft UP 2.5 inches
Because the bravo is 2.5 inches shorter than the TRS.
I never measured before disassembly but if I measured correctly:
Prop centerline is:
2.75 inches below the pad.
7.25 inches below the v portion directly in line with the prop centerline.
9 inches below the flat portion of the notch.

I was thinking of dropping the engine 1/2 inch. This would raise the props 2 inches.
If this gives me problems I can always buy spacers.

MAX HP this old boat will see is in the 600 range.
Opinions please!

DS

Here's a photo of my transom/ bottom

Here's a photo of a 1980 Executioner:
Same bottom