Alpha 1 identification (how)

[Planetwarmer]

The previous owner of my Alpha 1 repainted it. Is there any (easy) way of telling what the drive ratio is? It is an 87' mated to the 454 MAG all original.

THANKS

[DONZI]

Note the exact location of the prop. Note Crankshaft balancer location, make one full revoultion of the engine by hand w/drive in gear and see how far prop rotates.
One and a half=1.50.:)

[Planetwarmer]

Sounds easy enough. Thanks

[smokediver]

most of the big block and alpha drives were 1.36 ... i think ...

[smallblockford]

what size boat.

i disagree with 1.36

will bet on the 1.50 since it is original which meens it is 87 or so on back before the bravo then about in the early to mid 90s they started runing the 1.36 in some bravo big block aps but i have a 240 baja in the shop now with stock 7.4 360 mag 1.5 alpha i built the drive a while back for the guy she is still holdin just dont jumpem and snap the shaft at the oring groove

[MR MAGOO]

I've got a 1987 Pachanga with the stock 454 Alpha combo. It's a 1.36 ratio. As mentioned above, I believe all 454/Alphas were 1.36 from the factory.

[Formula Jr]

'87 to '89 454/Alphas were 1.32:1

Alpha 1s never had a 1.36:1; Bravo 1s did.

:popcorn:

[penbroke]

Note the exact location of the prop. Note Crankshaft balancer location, make one full revoultion of the engine by hand w/drive in gear and see how far prop rotates.
One and a half=1.50.:)

Actually, it's the other way around. You want to turn the engine untill the prop makes 1 full turn. 1.5 engine revolutions for 1 prop revolution would be a 1.5:1 ratio.


Frank :lookaroun:

[Formula Jr]

Thanks Penbroke, you got there first.

Donzi, the first number is the input rotation, the second number is the output rotation. Its a gear reduction if the first number is bigger than the second number.

So with a 1.32:1 ratio, one revolution of the engine will spin the prop about 273 degrees or just past 3/4ths of a revolution.

:popcorn:

[smokediver]

'87 to '89 454/Alphas were 1.32:1
Alpha 1s never had a 1.36:1; Bravo 1s did.
:popcorn:
actually , they did ... and a 1.30 ... go figure ... seems they were having problems with the 1.5 gearset behind the big block and messed around with a few of the lower ratios ... not sure of the years ... i dont think .02 or .04 is gonna make a that much difference , lol ...

[MR MAGOO]

1987 454 Alpha One, 1.32:1 ratio

http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=%2099964&ivar=images/CRUISER/99964/30066.png&inbr=2203&bnbr=70&bdesc=DRIVESHAFT+HOUSING+AND+DRIVE+GEARS