I have a 2006 454 mercruiser matched up to an Alpha I on a 1987 Baja. It is carburated and have been told it runs at 330hp. My current prop is a 19 pitch. My question is what is the max RPM that I should be able to do.
I have a 2006 454 mercruiser matched up to an Alpha I on a 1987 Baja. It is carburated and have been told it runs at 330hp. My current prop is a 19 pitch. My question is what is the max RPM that I should be able to do.
As you probably already know a BB in front of an alpha drive, means you have to be careful with your left hand. Gradual starts vs full throttle launches, etc. The alpha will not take the torque for too long.
I'm not up to speed on the BB, but expect that wot rpm is probably in the 4600-4800 range. I believe the few 454/alpha combos sold by Merc had 1.3 drive ratio. Not sure if this was just an engine replacement or a power upgrade, so you would want to confirm drive ratio. If it is a 1.5 ratio, still might get bye.
4600-4800 sounds too high.....I have a 1980 454 Mercruiser model MIE330 (330 hp) Inboard.....Max rated WOT is 3800-4200 rpm right on the motor sticker. They made a 454 model MIE340 (340 hp) with a Max rated WOT of 4000-4400 rpm.
From looking at service manual #16, the 300hp version had a recommended range of 4200-4600. The 350 and higher hp version is 4600-5000. #23 just had MPI versions, but similiar ranges. The MIE (310hp) version was lower 4000-4400.
Thanks guys that helps a lot. My mechanic is doing some caculations to change my prop. One last question I have heard of a company that rebuilds Alpha's to better match up to BB anybody know who that is.
Thanks guys that helps a lot. My mechanic is doing some caculations to change my prop. One last question I have heard of a company that rebuilds Alpha's to better match up to BB anybody know who that is.
