I think I would go through that engine before I would install it in a boat. Looks to have been neglected. Noticed the date on the pics. Has it been sitting in the yard under that blue tarp for 7 years?

Yea ill crank it up before buying it so it should all bolt
Up and move 1 ft forward?

you will need to have inner gimble plate installed to get your measurments for engine mounts

The matching engine to this one in the boat overheated from a crack block or some other issues in less then a couple of hours of running it, so check it out before buying it.

Correct magnum I was told by the guy that the other motor overheated because it had a cracked block.

I meassure right now I have a 454 with alpha 1 and I have exactly 12 inches from the engine to the firewall I guess it won't fit

Wouldn't it be easier to just bolt up a Bravo? Same transom cutout hole. +2 more holes in the transom for the transom assembly and a couple of bolts? And a better selection of inexpensive props. I think this is going to become a mess pretty quick.

he should be able to sell the transmissions and ssm drives for more than the cost of bravo drives,i would think.

I guess It's better off selling my boat and buying another one with a worthy drive installed...

Not at all. It would just be easier to install a Bravo then converting your Jaws to a transmission and #drive boat. Also as Mike stated earlier I think you would be money and labor ahead if you did the Bravo conversion.

My dumbass would run the Gen2 Alpha till it popped. Weighed the hours and cost of another Vs. the $$$ of the conversion. You have a small light boat. If you get a season or 2 out of it that is a bonus. And you can replace the upper or lower with an inexpensive SEI. I don't think you are getting much out of an Alpha selling it on Craigslist.
I would be more worried about that engine than finding a drive. Make sure it runs on a stand before you buy. Then leak down test.

http://www.sterndrive.cc/

i would go with rookie's plan. plus the alpha will run bravo props. you can see how the boat likes the current prop height with that much power, then get a bravo set-up, and with a shortie and spacers you have lotsa options for x-dim.