I'm researching different types of long blocks for my Wellcraft. I have 1995 Gen V 7.4L in their now. I have been looking at US Engine at their website about 454 Magnum motors with 2" rectangular ports that have 55 more hp and torque in the 1500 to 4000 rpm range and use 20% less fuel than the original mercs. I have a Magnum in my other boat and I love that engine and it's performance. My question is will this in any way affect the Hurth transmissions I have in my boat and will I have to reprop as well? Any advice would be appreciated.
First I don't believe their claims about horsepower and especially efficiency. Otto cycle technology (throttle and spark plugs) just doesn't support efficiency swings like that. If they are that good they should be building engines for GM
What model Hurth? Specs? What hp rating in there now? Carbed 310?