When they " fill-in " a transom hole to re-cut for another outdrive?

Do they replace the whole transom, or fill in the existing hole?

I have a line on a Volvo-Penta Intermediate, and leg from a burned out
Bayliner. The burnt Boat came with a V8, and I can get both really
cheap.No engine or controls are included. I'd have to find that. I've
been talking to a Marine Mechanic who sells Volvo parts, and tells me
the drive in question are practically bullet-proof. This model can
also be converted to a Duo Prop.
The good thing is there wouldn't be a huge hole like the one needed
for the OMC Drive.

Anyone converted a Boat like this? Anyone know anyone who did this?