First of all they are 8.2L engines also known as 502 cubic inch engines. From what I understand they are basically gen 6 502 GM blocks that Mercruiser assembles with a GM crankshaft, forged rods and someones forged pistons. They have a new version of Mercury's 502 Edlebrock cast and built cylinder head with a slightly modified HP525 intake with a new round 90mm throttle body and a fairly mild hydraulic roller camshaft. They are equipped with the same catalytic exhaust system that was fitted on the early 2010 496's. When they are ordered for an existing boat for re-power they come less the catalyst system and standard 496 type exhaust manifolds and risers.
I have not heard to much in the way of how they are holding up but I had heard that Tyler Crockett has done some warranty repairs on a few with internal issues. The problem with feedback at this point is that so few have been sold and in use that there is not really a good sampling of customer use and feedback.
I will be really curious to see how the catalytic converter emission systems hold up in actual use, especially in salt water?
I personally think that this catalytic emissions system may be the initial achilles heel of this new engine.
Hopefully Tyler or some users will come back with their information or feedback.
Ray @ Raylar