your local GM dealer, summit racing, your local engine builder.
nothing special about the motor. its a 1996 and newer GM 5.0 block and heads with brass or stainless core plugs, marine head gaskets and the marine stuff bolted to it.
There's a reason Mercury/Mercruiser assembles their own engines. A marine engine operates at much higher RPM's for much longer periods of time than an automobile engine. This makes having a well-balanced engine much more critical. Mercruiser balance-matches sets of pistons/pins/rods to obtain the lowest out-of-balance weight before they assemble the engine. If you buy an automobile engine to put in a boat you should balance it to within 4 grams preferably 1 gram. Then you have to marinize the block with brass freeze plugs and a marine water pump.
There's a reason Mercury/Mercruiser assembles their own engines. A marine engine operates at much higher RPM's for much longer periods of time than an automobile engine. This makes having a well-balanced engine much more critical. Mercruiser balance-matches sets of pistons/pins/rods to obtain the lowest out-of-balance weight before they assemble the engine. If you buy an automobile engine to put in a boat you should balance it to within 4 grams preferably 1 gram. Then you have to marinize the block with brass freeze plugs and a marine water pump.
Notice no pics of long block internals ? Believe it if Merc was going above and beyond GM specs on their balance job they would certainly be touting that point and would have included that in the video.
having been a vendor for Mercury/Mercruiser for years and personally knowing about 40 of the engineers in Fond du Lac (and formerly stillwater), the only long-blocks they assemble for the mercruiser line themselves are the ones they cast themselves along with the stroked small blocks and the big blocks since GM doesnt offer an OE version of the stroker and they quit offering big blocks in 2008. Mercruiser purchases the 8.2liter (502) blocks from GM performance parts division and they do assemble their 6.2's which is a GM performance 350 block with a cast stroker crank
since mercruiser no longer offers the 3.0 and is now casting their own V6's and V8's they no longer buy complete motors from GM. however prior to the release of the new motors and severing the relationship, they did purchase the same long-blocks from the Tonawanda plant that everyone else did.
The only long blocks you could get from Tonawanda recently up until GM made the big reinvestment for Gen V 2 years ago were 4-cylinders. Unless you want to go way back.
OK to put an end to this I called Mercrusier customer support. They DID NOT assemble or balance the long blocks that they received from GM. That being said they no longer use GM engines due to GM going all aluminum and the Mercruiser engines being cast iron in the intrest of corrosion resistance to salt water.
That is simply not true. I don't know who you spoke with but level one customer support may not even know about these things.
Once again, watch this video of the production facilities. https://www.youtube.com/watch?v=gXDFmv1Fcqw
Notice at around 12:40 the narrator says "once the longblock is assembled". That is a GM components engine that they assembled.
OH YES we all know everything on the internet is true...and it only says "after it is assembled"...not "after we finish assembling it" Believe what you want. I believe the guy at Mecruiser. The only engines they balance are the Racing engines.
This is not just some video on the internet.
It is published by Mercury Marine.
And quit trying to change the words. I gave you the exact quote in my post.
Parts matching for balance is simple. The computer does the whole job. We're not talking about 3-plane race engine balancing.
I get it, you have some kind of thing where you want to believe that you can take an auto crate engine and stuff it in a boat and everything will be fine. Please by all means go ahead. That engine will never last as long as one assembled by Mercruiser.
op2: