Their stock varies, and their website often doesn't tell you everything the have, but I've had pretty good success getting Mercruiser M/R and pre-Alpha stuff from NLA Marine in Michigan, and noticed they have a lot of newer stuff as well.
I've also gotten stuff from Shipwreck Salvage in Chicago. They show a bearing carrier you might be interested in.
http://www.shipwrecksalvage.net/inde...oducts_id=1797
I did once buy a pristine-looking manifold for a 3.0 Mercruiser from Shipwreck Salvage that looked great, but ended up being cracked. They replaced it with another manifold that wasn't nearly as nice looking, but was corrosion free, which was really what I was looking for. I did, however, have to pay $25 shipping for the replacement manifold.
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Common Sense is learning from your mistakes. Wisdom is learning from the other guy's mistakes.
Fr. Frank says:
Jesus liked fishing, too. He even walked on water to get to the boat!
Currently without a SeaCraft 
(2) Pompano 12' fishing kayaks
'73 Cobia 18' prototype "Casting Skiff", 70hp Mercury