Yannis and others,
Those are definitely 6LPAs and are 6 cylinders (look at the 6 injector lines).
The hull stringers have not been cut. They are not visible in the pictures as they are covered with a structure that has been built to fit these engines.
Much like the original engine mounts.
Also, remember that Bertram built a number of B28 with 6 cylinder Volvos installed in the factory. These boats have a significantly different, bigger, engine compartment, and can accommodate the 6 cylinder motors. I would guess that this is one of those boats.
To get a better look at the hull stringers and how my boat was modified for the 4LHAs go here.
https://www.sbmar.com/repower-projects/ ... board-way/
We simply removed the wood engine supports, which were bolted to the hull stringers and laminated to the bulkhead. Then re-enforced the entire engine room (glass).
I would guess that Greg's boat is one of he ones originally fitted with Volvos.
Bill