mercruiser 470 replacement?

[surchin]

Well, it appears I may have terminal problem on my 470. it was running fine over july 4, but last weekend It would not crank on starting and we pulled the plugs, a little rusty and the flywheel will not spin with a wrench on it.

I trust my boat shop and they are going to pull the drive to see if its the drive or the motor that is locked up. I am thinking worst case and they are recommending a "bobtail" replacement with a 3.0 L motor ?

Any one done this? $5200 is a quote for the motor. plus labor

Any experience here please ?

Thanks
Scott
santa barbara, CA