is this an alpha 1 outdrive?

[chaddemler1980]

can anyone tell me if the drive in this pic is an alpha 1 or a pre alpha? need it to fit my boat "alpha 1"

 

[Bt Doctur]

Re: is this an alpha 1 outdrive?

Hard to tell, the series 1 has a round cavitation plate and a top cap with a lifting eye, Alpha has a square cavitation plate and a recessed lift eye.
what you need to know is what ratio it is. Series1,Alpha,R,MR,all will fit but the gear ratio will determine how well it performs.

 

[Fishermark]

Re: is this an alpha 1 outdrive?

Yeah, the pictures are mighty small. Here is a link with more info:
http://www.mercstuff.com/drive_id.htm

 

[chaddemler1980]

Re: is this an alpha 1 outdrive?

ok guys a little more confused got 4 new pics close up i think it is an alpha 1 but 1 of the pics dont match what they say but it may just be a replacement prop shaft, merc said it is supposed to have a letter "A" stamped on the end while a pre alpha has nothing, well mine has nothing but the other three pics resemble a alpha 1 perfectly.. you tell me your opinion? and also how do i determine what ratio it is... should it be a v8 small block? the guy said it came from a v8 but did not specificly say it was from a small block or a big block... but others tell me they should not have used an alpha 1 on a 454 big block.

 

[Fishermark]

Re: is this an alpha 1 outdrive?

Looks like an alpha to me - and yes they did put them behind big blocks for a short time... till they learned better.

 

[Fishermark]

Re: is this an alpha 1 outdrive?

Again, hard to tell from your pics... is the area around the top vent hole smooth? Or does it have ribs? If smooth, then you have an alpha.

 

[Don S]

Re: is this an alpha 1 outdrive?

It's an Alpha I, and Mercruiser did use them for a few years with a 454, then they invented the Bravo drive.
Put the drive in forward and turn the ujoints clockwise and count how many turn how many rotations turns the prop one full revolution.
1 and 1/2 turns is a 1.50 gear ratio for a SB Chevy.

 

[thumpar]

Re: is this an alpha 1 outdrive?

Does anyone have any idea about the "A" stamp on the prop shaft? Mine also doesn't have the stamp and confused me at first. Is this a replacement or are some just not stamped?

 

[chaddemler1980]

Re: is this an alpha 1 outdrive?

what other ratios should i be looking for instead of 1.50? what ratio was a 454 big block? if it is not a 1.50 ratio and is instead a ratio for a big block can i still use this on my 350 small block?

 

[Don S]

Re: is this an alpha 1 outdrive?

With a big block, it used a 1.32 Gear ratio.
On a Small block, it will be a real dog, and you will never get it propped to work like it used to with the proper gear ratio.

 

[chaddemler1980]

Re: is this an alpha 1 outdrive?

well i did the rotation test and it was to close to call whether it was a small block 1.50 or big block 1.38. i guess your opinion is whats needed. i put alignment tape on both the prop and the drive shaft. i turned the prop exactly 1 turn and stopped on the tape mark exactly when i looked at the drive shaft it was maybe a 1/4 inch off "less" from being a full 1 and a half turns. i suppose this could be from slight play? im not sure really how close a call it is cuz to me that would put it right in the middle of a 1.50 and a 1.38 or it if it is tight than and there is no play "which i really felt non than it would be a 1.38? any other suggestions besides having a rookie "like myself" open the case up and count teeth? and also if it is the big block 1.38 would a local marina be willing to trade mine for a small block 1.50 or would i be paying out the nose still?