Hey another 25 twin engine Lancer owner! T
here are two types of classic 25 hulls here on The FORUM, and these are the 25 Tournament Fisherman that originally came with inline 4-cylinder motors, perhaps eventually with V6 power I'm not sure (Jerry is converting one of these to small block Chevrolet power now), and then the 25 Lancer of 1969-1971 that started with serial number ORAZ-25 which I think you have.
In any case the Cat 6.6 is going to be a lot of iron in the back of the 25 hull, I'm not saying it can't be done, as I rarely use the "C-word". That hull is balanced for a pair of Buick V6 motors and those things even with iron marine exhausts would weigh about half what the Cat weighs which is about 1100 pounds without marine exhaust as I understand it.
The 25 hull is a good one, it is one of the Jim Wynne designed hulls and it should be quite formidable in open water. With the right out drives and a pair of those diesels, you would have something nobody else has. There may have been some of these built in Europe by Herb Pocklington, perhaps with Fiat or Perkins diesel power, but to my knowledge this model never got diesels here in the US.
Sounds like a fun project, keep us posted, you will find there is a wealth of information at your fingertips here if you can just tap into it; most of that info will come back to you in the form of postings from very knowledgable people who are willing to share.
As you get into your project send us some photos!