I have a 1986 37 Bertram w/ 6v71’s @ 435 and 2” drive shafts. I’m getting ready to to repower with 6v92’s (550’s) and would like to know if they ran the same 2” shafts and same twin disc transmission(s) as the 6v71’s (435) and 6v92’s (450)? I realize I’ll have to re-prop the boat as well but just wondering if much was changed between the 450’s and 550’s. From what I’ve gleaned from my manual and one I’ve downloaded from the internet, the 6v71 and 6v92 @ 450 are identical as far as transmissions and propping.... Other info: (always a) fresh water boat gets used about 70-100 hrs a year, Detroit’s and people to work on them are easy to come by in Michigan. ...and yes I would love to do a Cummins C conversion but figured a swap to 92’s would be the easiest and least expensive route for the limited use the boat gets 1350TT since new (1986)!