300R...4.6L...V8....Potential HP?
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Cant comment on Mercury but from engine design, you need to pull compression with a FI engine in order to make it last. Typically you see between .7-.8 power more with FI then NA. For instance if you took a 300hp engine at sea level and forced 14.7psi thru it, you should double the power(double atmospheric pressure), but you have to pull compression in order to make the engine last along with timing to run on pump gas. At 300hp at 14.7psi one would see 510hp. Not sure what the 400r runs for manifold pressure to achive the 400hp but typical in a gas application you wont see much more then 1bar of manifold pressure on pump gas.
Short answer I'm guessing around 500hp.
Short answer I'm guessing around 500hp.
an inline six is the most durable engine design period. Look at all the inline 6 diesels. 7 mains one rod per crank throw and perfect balance. I think merc can shave some weight off the six with no cyl liners and other mods like lighter trim rams etc. I like the straight six design. I think the diff between the verado 300 & 350 is it picks up 50hp just by cooling the intake air charge with a water cooled blower. The two engines get the same fuel milage! Add a big inter cooler better porting and that engine can make a lot more hp without adding a lot more boost/cyl pressure.imo
look at the ob weight vs a merc 500 i/o set up.
Here in Colombia the tourist boats that were running 200hp 2t engines are replacing them with 150hp 4t engines and carrying the same weight and same speeds but use 28 gallons round trip vs 42 gal for the 2t but the big savings is @ 100 hour oil changes you use 12 qts on the 4t engines vs 187 quarts of 2t oil in the same 100hours. That equals an extra 2k dollars in your pocket every 100hours or six weeks with the trips these boats are making.
That being the case. Mercs new 300 4t at actual 315ponies is out performing their 2t 300s and should last longer...
i was worried merc was going to discontinue the verado straight sixes.



