Metan in the northeast has retrofitted some 23' CCs with jackshafts. (See below link) Motor under the center console and a Volvo Penta duo prop outdrive. It might have been a diesel too (Yanmar), I can't remember. It was a beautiful boat. I think they were asking $125K! ��
https://www.youtube.com/watch?v=IDLwnWmhYtc