Re: Will Alpha 1 outdrive hold up with hopped up 5.0 mercruiser
To make a 305 produce that amount of power will require a lot of top end, higher revs than a drive will take. It will also mean a loss of low end torque, making the boat undriveable at lower speeds. The only way to make the sort of power you seem to be looking for and retain a degree of 'driveability' is to get a much bigger engine, something like a 8.2 litre, but even they are only producing 430hp in standard configuration. And you'll need a Bravo XR drive.
Ok, on to the boat. I've searched and found a few pictures of your boat, nice looking. I suspect it's slightly lighter than mine. The hull deadrise looks a little less too, so I can tell you that my 220hp V6 shoves my boat along at well over 40 knots, but to get to 50 I suspect I'll need more like 350hp. It's all about the exponential. To double your speed you need something in the order of 4 times the power. I would think the 305 is pushing you along at about 28-30 knots. To get to 45 knots you'll need about 400+hp, and you're not going to get that from a 305. I've also looked up where you use the boat, your on the Atlantic Ocean! The number of days you'd be able to excess 40 knots in a decade would be able to be counted on one hand. I would think a cruising speed of 18-24 knots would be more the order of the day. To have a 305 with that much top end would mean a cruising rev range of around 2000-2500rpm, and that engine at those revs would NOT be a happy camper....
'Nough said.
Chris.....
