Re: Gas milage, 2x454 vs 2x540
 

I bought my 272 Formula with t 454/330s and did 1.5 mpg at cruise 3000 rpms and 42 mph with 25 Mirages. Changed to 625 hp 540s and at the same 3000 and 28 Bravos , now get 50 mph and 1.1 mpg at cruise.
If I slowed to 42 mph my mileage may improve. Because no matter what hp you have in a boat , it's still going to take the same number of hp to move the same boat. The bigger engines will be propped higher and turn slower.

Re: Gas milage, 2x454 vs 2x540
 

I run a 79 30ft scarab with 2 540 pump gas motors. Last summer on the chicago poker run we ran 109 miles and i only used 75gals. My boat is very heavy and most of the time we were running in the high seventies. the boat runs right at 90mph. Thats with 26 pitch quad IV props and the motors spinning at 5800 TRS drives. Brian

Re: Gas milage, 2x454 vs 2x540
 

Both engines would burn the same if tuned by the same standard regardless of cubic inch.