Possible to convert turbo D2-75 to non-turbo D2-55?

[SweareDeep]

I have a D2-75F which was an upgrade from the D2-55 when I ordered my boat. A couple of years ago it was found that the D2-55 does not meet US emissions standards (yes, we still have some standards) and they all had to be recalled and replaced with the turbocharged D2-60, so either way I would have ended up with a turbocharged engine.

Last winter, I had the yard remove my turbo for precautionary service. They said it looked fine and didn't need either rebuilding or replacement. If we're motoring, other than in harbour, typically it's at 2000-2200 rpm and sometimes for quite a few hours, so perhaps that's sufficient to keep things in good order.

I went with the D2-75 because I've had two previous boats that were chronically underpowered (one could barely make any headway into 20 knots of wind) and I'd much rather be overpowered than underpowered (not that my boat would necessarily be underpowered with the D2-55/60.)