BoatBanter.com - View Single Post - 5.7 Magnum 350 MPI 300HP Mercruisers mated to...Alpha One outdrives ?!?

On 9 Mar 2005 03:09:23 -0800, wrote:

Hi Tony,

I've checked the google groups for info on 5.0 engines, and apparently
the stock cam is already the one which gives the best torque at 3000rpm
(please correct me if I'm misguided).

So it looks like I'm back to square one - which version of the 5.7 or
another sterndrive compatible engine - if anyone has suggestions.

Be careful here! There is a world of difference between the cams in a
marine engine and the one used in the same engine in an automotive
application. When comparing engine specs, make sure they are for the
marine engine.

Most marine engines deliberately cam the engine to develop max torque
HIGHER in the RPM range. Most marine engines develop peak torque in
the 3800 - 4000 RPM range. Most marine engines operate at high RPM
most of the time, so the torque is speced where the engine is run
most. In a land-based application, a car engine rarely cruises above
2000 RPM, so it's cammed to produce torque at a lower RPM.

Dave