If my memory servs, they're both the same block ie "that old Nail" Chevy.
"and is the 5.7L volvo much different in running costs???!!!!!!!! " Not that you'll notice, cos they'll both empty your wallet faster than a divorce settlement.
Mercruiser and Volvo share the same engine blocks on many occassion, and on many occassion, if not all occassions, the original block is General Motors. There will not be a great deal of difference between them (5.0L vs 5.7L) on running costs and they are both reliable if looked after.
<hr width=100% size=1>Madoc Yacht Club
<A target="_blank" HREF=http://www.madocyachtclub.co.uk>http://www.madocyachtclub.co.uk</A>
All the current/recent Merc & Volvo petrols are GM base units.
In Volvo's case, all engines designations are eg: 3.0GL, 5.0GL etc etc the 'G' because the base engines are GM.
The older series VP petrols eg, 5.0FL, 5.8FL these were Ford based units. The even older kit like the AQ211, AQ271 etc these too were GM.
In the case of a VP 5.0 v's 5.7 you would likely see the following, to be considered as approx only as drive options SX/DP-S, sea states, hull type etc..
5.0GL (220hp @ prop) 43.6ltrs/hr cruising - 72.6ltrs/hr full load
5.0GXi (270hp @ prop) 49.5ltrs/hr cruising - 96.7ltrs/hr full load
5.7GL (260hp @ prop) 56.2ltrs/hr cruising - 93.6ltrs/hr full load
5.7Gi (280hp @ prop) 56.6ltrs/hr cruising - 94.5ltrs/hr full load
5.7GXi (320hp @ prop) 68.9ltrs/hr cruising - 114.8ltrs/hr full load
Service costs, all very much of a muchness when looking at these V8 engines.
Not sure if this is off line to the information you wanted but speaking to Volvo and mercruiser dealers have discovered that mercruiser guarantee full warranty back up anywhere in the world irrespective of location of purchase, this seems to happen in actuality, whilst there has been grumbelings in the trade that Volvo dealers have in the past put up more of a fight if warranty work is needed and the boat originates from another country. I was thinking in the terms of the boat being moved about.
As i say possibly not anything worthwile but thought id mention it. Please I am not saying they wont do the work but that problems have arisen from the above with regard Volvo.
I broke down in Dartmouth this summer. Had to call out the local Volvo engineer. He did find it nececary to point out that he would have to inform volvo and have my three year old gear boxes, banned from Waranty. So it apears that the Volvo agents are the Volvo Gistapo or secret police designed to find any posible loop hole that Vsplutter can jump through.
<hr width=100% size=1> <font color=blue>No one can force me to come here.<font color=red> I'm a volunteer!!.<font color=blue>
Its not on really I know of dealers who supply boats that can be powered by both Mercruiser and Volvo but should the customer be moving the boat to a different location after purchase they will always sway them to the Mercruiser unit for that very warranty issue.