1974 Columbia Mk II
Which Columbia MkII? Columbia had models in a number of sizes that were MKII''s of an earlier model. There is a big difference between putting a new diesel in a 31 mk II and a 36 mkII, if you see what I mean.
In any event, in their day, Columbias were pretty much middle of the road, or slightly below, production boats. They were heavily built by today''s standards but that does not mean that they well engineered. Finish wise they were a step down from Pearsons and were not quite as robustly built.
At this point, they do not have a lot of resale value, even in really good condition so piling a lot of money into one is not a great investment. If the boat you are looking at looks great, has really good sails, no blisters, deck rot or other major structural issues, and the rigging and upholstery has been replaced, and deck and interior hardware and electronics have been upgraded with modern gear, this might be a good deal even needing an engine.