Alpha to Bravo swap?
01-05-2006, 06:59 PM
#11
Geronimo36
Gold Member
Re: Alpha to Bravo swap?
Originally Posted by Big Block Billy
The gears are $408 from Bam. I have not seen them aftermarket. Make sure that they are shimmed perfectly. I did one for someone this summer, It's a pain and it takes a while, taking it apart , preloading, moving shims, checking clearance, pulling bearing races, etc. It may have to come apart several times to get everything right. The Merc. book must be followed to a t. Also at least check the backlash on the lower. If not done right it will shear the pinion gear right off. This happened to me when I had some local shop put a drive together, before I had all the tools. Make sure everything in the drive is good. Bearings , seals, etc. Also should go with improved shift spool in lower unit unless it already has one. 1990 and up should be stainless instead of brass. BBB
Upper is similiar, check drive gear hight, then rolling pre-load.
I got so used to setting up Alpha's that I could set the backlash by feel but, I wouldn't recommend it.
I don't think I could do it without the book nowadays, it's been a while. 
Re: Alpha to Bravo swap?
01-08-2006, 02:45 AM
#14
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Re: Alpha to Bravo swap?
I would have to agree with you Big Block Billy. I've seen a pair of 454/420's on Alphas in a 26' Sutphen. It has not blown a drive yet. The boat runs over 70mph. Plus, the parts and new prices on Alpha drives are much cheaper.
01-09-2006, 08:07 PM
#16
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Re: Alpha to Bravo swap?
I had a 1988 22' stingray with a bb 602 hp pushing an alpha short drive.The only upgrade I had to do was a thru hull water pick up.The alpha just could not keep up with the demand to keep the engine cool.But I ran that boat for two years with no problems at all.I sold it last year to a guy in Virginia.Just take it easy out of the hole and keep it in the water on waves and you'll have no issues.
Anthony
Anthony
03-22-2019, 05:35 PM
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Meaning how hard you are hitting it out of the water?
I am looking at an old Formula with twin 350 magnums and Alphas. I don't know that I would ever change anything, but if I did have to rebuild or replace engines I am guessing Id go a bit more powerful. But I have hot rod boats if I want to hit it hard out of the hole.
Thank you!
J
I am looking at an old Formula with twin 350 magnums and Alphas. I don't know that I would ever change anything, but if I did have to rebuild or replace engines I am guessing Id go a bit more powerful. But I have hot rod boats if I want to hit it hard out of the hole.
Thank you!
J
09-02-2019, 08:14 PM
#20
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Reviving an old thread. The shock load that's referred to is when re entering the water. The prop bites at high rpms and things can shred. So if you get air in a higher powered alpha you'd best modulate the throttle while the prop is free of the water and hit it again when reentering.
I just make sure not to break grip.
I just make sure not to break grip.
