Saying that the 6-71 is bad engine is not a true statement. Being in the size boat that these are in and being that they are TIB series they must be the 485hp rated models. 2 words-stay away. This is way too much power to push out of a 426 cubic inch engine. 1500hrs is a good life out of a brand new one. The inline sixs are little better then the Vee configurations but neither is a good plant. There are also 450hp and 410hp versions. These are alittle better, though the lower the horsepower, lower the stresses on the engines. Detriots are brutally tough in the lower horsepower ratings where they just have roots blowers or the lowest turbchargered version. A viking this size should have 6 cyl 92 series if its going to be detriots. Do yourself a favor and find one that has been repowered with something else or has 92 series in the 400-500hp range. They will push 575hp out of a 6-92 and it becomes the same bomb that the cranked up 6-71 tib is. I have seen 40,000 hrs out of a 6-71 genset rated @ 165hp so in the right application and rating, it will be a good engine but not the way they get turned up in these sportfishers.