I have twin Pre Alphas...

as much as I would love to upgrade, I need to get this boat wet and test run before I go all out.

Both Lower Cases need work. (One pretty badly) I fear it may be cheaper to just replace the lower unit (Or Case) as opposed to repairing them ...

How do I know what lower unit will interchange with mine?

is there a quick easy way to tell?

Mine are pushed by Mercruiser 260's

What year is the setup? Pre alpha lowers are going for $250-400 on ebay.

Order the SEI's

2nd that

what for once you finally agree with something that I said ??? ^^^^

SHHHH!! your going to ruin my reputation.....-

Whoa. Aren't the SEI units Alpha replacements? What about the pre Alphas? MMR, MMR1?..or something like that?

BTW..phragle..your AvantI is my Condor reincarnated. I'd love to see more pics.
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1972 thru 1990. I can help a bit with price and all warranty is thru SEI only. There is not much profit for dealers keep these on the shelf. Order as we go. Link is just an example as gear ratio would have to match.

http://www.sterndrive.cc/product/Fit...o-1471017.html

The Boast is a 1980 model . So I would bet on 79-81 units.

The Starboard unit is missing a nose cone (doubt I will find another like that...

Any Alpha I replacement drive will bolt up to the Pre Alpha gimbal with no issue. At the time of the swap it would be a good time to replace the exhaust, u joint and shift cable bellows.