I have recently come across a really nice, clean 2003 Monterey 208si powered by a 305 Volvo Penta engine. The owner failed to drain the engine one winter and, well, it's ugly. I think the boat can be had for a very low price, for obvious reasons. I have an '85 Citation with a tired old hull, but a strong running 1978 Mercruiser 260 power plant. This engine was swapped into the Citation years ago. I've read here that the transom cut outs for Mercruiser and Volvo don't match up, but the blocks are the same. Is it possible to just swap the blocks? Am I crazy to even think about this?
Thanks in advance for anyone's advice
Jonathan

I would sell the old rig. Use the money to buy a brand new longblock. Swap the all the stuff on the new motor.

Sound advice, if I thought I could get enough out of the old rig. It has hull and outdrive issues of its own, or I would not be looking to replace it. The motor is strong, and I'd love to see it live on in a new hull.

If it were my boat, I would go on craigslist and buy a $300-$500 350 out of a 1998 or newer chevy van/pickup. You would get roller cam, vortec heads. You would have to buy a $160 intake manifold though. But for probably $750 you could have a nice running 350, and still sell your old boat for a few bucks.

It takes money to make money .and your best engine swap to the Monterey ,if its carbed.,is a Vortec 350..you will have to buy the boat and tear down the motor .if your lucky the old cam and heads are good and you find a 305 block .

Grab a Vortec 350 from the junkyard and put the heads, intake and accesories off the 305 on it.

Swap the bell housing coupler and front motor mounts for the volvo ones.and it will bolt right in, all accesories should swap right over. Basically a volvo 305 and a merc 260 are chevy smallblocks. There are adaptors out there for the wiring if needed too.

Not quite that easy if the 305 is a 1 piece and the 260 is a 2 piece. Personally I think if you swap an old 2 piece setup into a nice boat that had a 1 piece setup you are making a mistake.

What your making is a running boat you can afford and enjoy. Now if you want to go fast etc.....its going to take a bit more work., if your goal is to go for a boat ride, do what you gotta do to make it happen.

Unless that sucker is pink or had people disemboweled on the interior a 03 open. Bow Monterey is a 7k boat on a bad day ill bet your gonna get it for under 3 grand . Now that the cam has probably marinated in milkshake swill while you debate whether or not to grab this thing while you can , you can still get a Vortec 350 cheap ,a correct non emmissions non truck roller cam , cheap jets for 351 app for the Holley 2bbl (if not fi ) cheap and have a nice boat cheap .
Cheap cheap cheapety cheap put your 260 on a stand and hold out for a cvx23 with a cobra
If your 305 heads didn't crack and are presentable those are worth suprising money .I can buy a good 5.7 for the exact same money as I can get for a pair of 059 castings .
Don't make me find this boat and buy it out from under you lol