III cutouts

So if i change to boxes or 5s later i would have to fill in the transom?

or IVs ... I have a guy who has a pristine set, and SSM boxes utilize a bearing carrier/support, you plug your drive into the transom assembly just like if it were mounted to the transom ... I have same set up except my boxes are 15" setback. same applies to a 10" the carrier is mounted off the rear inside of all SSM standoff boxes, deeper the box the deeper the carrier so a longer driveshaft would be needed, you will also need to change your transmissions to driveline transmissions.

you're making a drastic mistake to run a SSM III that high, it was not designed as a surfacing drive, the best thing to do on that Cig is to run the engines as close together as you can 33" to 35" Center to Center, and let the drives running surface do it's job around 3" below, otherwise you will turn this boat into a POS, the center of gravity/weight distribution will be out to lunch if you jack them up to surface a III drive, and again it's not designed to go that high up...
if surfacing is what you want then a SSM#4 or #5 is what's needed,
why would you want boxes in the first place?

I don't want them up high but right now they are pretty deep from what I remember so I want to get them up a little bit from there. The engines are are on 36" centers and we are not changing any of that. I really don't want surfacing drives just trying to move them up a little bit and get some more leverage for the bow. At this point I just want to make an informed decision so I know what my options are down the road. I don't want to have to re cut and refill the brand new transom I just put in.

Just to let you know the higher you go the less leverage you will have. Can you measure from the bottom up to the center of the top bolt holes on your transom I can give you your X dimension off of that measurement Regards Dan

Not the best pictures but it's the best I have