yukonridin23

well, fender jack, that would be a good idea if i planned on keeping the 454, but like i said earlier i plan to drop this 502 into by late summer and i know that will tear the alpha to shreads. i just would like to be out on the water if possible, a 454 in this boat will still be plenty of fun, plus i got the whole bravo xr with gimble for 3600 shipped, so for that price i might as well keep it. im a younger guy on a limited budget, so i dont have the funds to do it all at once, but step by step this boat will get their.

RdRacerZ28

This thread puts my mind at ease about using my Alpha behind the EFI 383 I'm building. Thanks!

searayed

I'm going thru the same thing - alpha 1 gen 1 on a 454. I haven't been able to find the proper aftermarket drop in drive - it should be a 1.32:1 ratio unit - sterndrive engineering offers a 1.47:1 version, but with no warranty. SE calls it their SE106. However, I bought the boat with an SE106 - I'm assuming it's the 1.47 version. that said, it lasted me only 1 full season - probably 3 or so before me, so it lasted the duration if it had the warranty. You can get the mercruiser 1.32 rebuild kit, which includes the gears and everything elso for $800 ish. So worst case: buy the SE106 complete unit for $1295 plus the rebuilt kit for $800, and put 4 hours in the rebuild, and you have a 'new' alpha 1 that will last properly. BTW, I am not sure why the 1.32 is called that - the gear ratio is actually 1.25:1 (the gears are 20 tooth and 16 tooth). If anyone could illuminate me on that, I'd appreciate it.
I have a heavy boat - about 7500lbs - for this setup. If I had the cash, I'd switch over to a Bravo 1 or 3, but that is an extensive swap, requiring the motor to come out, etc. I am currently wrestling with the choise - just put in an SE106 1.47 for $1300, or hope that my upper case is good and get the rebuild kit (which will require a new prop), or get a new upper case and do the rebuild.

1987pachanga22

My alpha gen 1 was used behind a 375hp 454 for the last 5 years on a 22’ boat and never a single problem.

searayed

What's the weight of your 22 pachanga? What ratio? I deal with gearboxes in my work world, and the rule is the lower the output shaft rpm, the smaller the allowable input motor, and it's almost a linear relationship. So you may be running a similar motor, but a higher ratio, which means your prop is spinning faster. I'm thinking I should be running a higher ratio, which seems to go against convention, but running a smaller prop that can spin faster, moving less water with each rotation. My top speed is much lower than yours (265 Sedan Bridge), probably half, so I could run the same prop as you but spin more slowly, but that would kill the drive. Ugh - I don't think I have all the pieces of this puzzle! But I'm not sure who does.

1987pachanga22

I don’t remember the ratio but I run a 19 pitch Ballistic prop. I do know that they are not the 50:1 ratio or whatever it is.