Fuel Consumption

[tartan28]

I am new to the Sea Ray site. I am going to purchase a 1987 26' boat. Does anyone know what the fuel consumption would be with the 454 engine versus the 350 block running the boat at 22-25 mph. I found a boat with the 7.4 ltr but not sure if that is the way to go.

Thanks,
Craig

 

[Sundancer]

I'd definitely go with the 7.4 on that boat. It doesn't work as hard and will probably get better gas mileage anyway. The 350 has to work pretty hard and once on plane doesn't have much throttle left. If it has the Alpha I, baby it! As long as you don't firewall the throttle the drive should last for a while. They weren't designed to take all 330 horses instantaneously!

I don't remember what we got with the 250 DA, but I think it was 1.2 to 1.5 mpg as a rough guess with the 454/Alpha I. We were pretty loaded with 4 folks and 2 dogs and a LOT of junk!

 

[chollyjohn]

I can confirm a similar situation. I purchased a 268DA NEW in 1988. I had the 7.4L with the Alpha I drive (known then as a Sea Ray drive painted white) It had the newer gearing which held up to the torque of the 454 block. My firend had a 1987 250DA. I got better gas mileage. On a trip from VA ot NC sdown the Intracoatal Waterway, I had a 19" prop; ran 28MPH @ 3100RPM and consumed 1 gallon gas per mile. When going slower, naturally I increased my MPG greatly. I agree with Sundancer, you need a 454 on that boat; a 350 block would be undersized and not as great a torque rating as the 454.

 

[BonBini]

tartan28: If your referring to 268's, one of our boat friends has a 87 268DA 5.7 260hp alpha 1.5:1 ratio 15.25x15 prop. I have 88 268WE 7.4 330hp 1.32:1 ratio 15.25x15 prop. I wish I could tell you some fuel consumption differences but we just never compared. I think we use close to the same when we cruise together at 25-30mph. The 268's with there narrow beam don't like to stay up good much below 25mph without trim tab help(wich really puts allot of drag on).

The differences: 5.7 needs pretty much wot to get up when fully loaded, the 7.4 does not(taking it easy on upper gear set). The 5.7 will make 35mph(260hp to push boat @ speed), the 7.4 will make 40mph(330hp to push boat @ speed). The 7.4 with it's single engine torque will lay the boat over to port when on plane. Single trim tab deployment will correct, but I think the drag makes her burn a little more fuel.

FWIW: I was at the GR boat show a few weeks back. Spoke with a Mercruser guy on the white painted sea ray Alpha drives, 330 horse big block coupled to a 300hp rating Alpha drive and all that.... He told me the 300hp rated Alpha's that were behind the 7.4's crashed right away, within very few hours of use. Heavy Duty upper gear sets rated for 400hp were manufactured right away, installed in replacement drives. This all lead to the coming of the B1.

IMHO: the 7.4 is the way to go.