Repower

deputyb

Cadet
Joined
Oct 27, 2009
Messages
7
I have a 1989 Sportcraft 270 Caprice. I have to replace the stringers and put new gaskets on my 7.4 l. Will I gain fuel economy by replacing the 454 with a 350? The boat is a straight inboard. I have the skills in the parts, just need to know if anyone has done this and can tell me if the fuel economy change is worth it. Thank you in advance
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,880
Will I gain fuel economy by replacing the 454 with a 350?

No
It takes power to move a boat, so replacing to a smaller motor requires the motor to work harder. In most cases it uses more fuel
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,581
It takes X HP to move your boat at a given speed. That doesn’t change no matter what power plant you use.

Either does the fact that 1 HP = 2,545 BTU/hr.

Unless the 454 is more efficient at converting BTU to HP than the 350 which is doubtful, the conversion buys you nothing in fuel economy.
 

deputyb

Cadet
Joined
Oct 27, 2009
Messages
7
Thanks guys. I suspected as much, but since the big block is coming out I wanted other opinions.
 
Top