Ford gt40 351 marine verse lightning

[rjrobin2002]

Just curious why the gt40 351w nautique efi boats had 310hp verse the gt40 lightning 351w trucks had 240hp?

Do yall know the difference?

 

[rjrobin2002]

Here is the boat motors

 

[Broncobowsher]

First guess, cam. The lightening had emissions requirements that the boat didn't.

 

[Yeller]

And cooling, virtually unlimited cooling. Although with the size of the radiator that could be gotten with an OBS truck I can’t see that being much of a reason

 

[DirtDonk]

And is power in the marine industry rated the same way it is in the auto industry? That difference looks suspiciously like the difference between net horsepower, and the old gross horsepower ratings.
However, it’s pretty common for boat motors to put out a lot of power for their displacement.

 

[rjrobin2002]

First guess, cam. The lightening had emissions requirements that the boat didn't.

Wonder if we can get the boats cam specs to compare?

 

[bmc69]

And is power in the marine industry rated the same way it is in the auto industry?

Marine power is rated, by industry standard, "at the propeller". If I recall correctly, the standard deduction for the prop power from flywheel power is -.03 or 3% driveline loss. The camshaft is the primary difference for a given engine that is produced for both vehicle and marine use. The peak HP and torque for a marine engine is achieved at a higher RPM than for an automotive engine.

Ford has gotten out of the marine market and Chrysler did quite a few years ago. We're left with Mercury (Mercruiser) and the monster Chevy engines they build. Of course there are still smaller third-party performance builders out there too. Here's a cute little 438 ci Ford engine I built for a boat....estimated HP is 480 but I have not put it on a dyno.

 

[Broncobowsher]

SAE net after a E4OD will have a good bit of loss as well.

 

[rjrobin2002]

SAE net after a E4OD will have a good bit of loss as well.

Were the lightning trucks hp rating at the wheels?

 

[Broncobowsher]

Not a the wheels. But with all ancillaries installed and running. Full exhaust, cooling fan, full intake with air filter. Power steering pump and the A/C. I believe that includes the transmission.