CB-BLR

What is the difference between the 310hp and the 330hp 7.4's ?

Also, how can one tell the difference?

Different years?

Chris

David Stotz

At some point in time Merc switched the HP ratings from crankshaft to prop shaft. It could be the same motor, just rated in a different way.

Dave

Pat McPherson

The 330HP is a Gen IV (1990 and older) 454 carb and rated at the crank.
A 300HP 7.4L carb is a Gen V (1991-1995) and rated at the prop.
The 310HP 7.4MPI is a Gen VI (1996 and newer) with GM fuel injection, also rated at the prop.

CB-BLR

Thankyou Pat,

That was extremely helpful information.

Chris