I've got a friend that has a 496 HO in an Advantage that he either forgot or just didn't get winterized for whatever reason. The boat is in Iowa and is inside of a metal building (not heated though). We have had lows around -12 F already this winter and it has not been above freezing at all the last week.

Is it too late to save his motor?

I would think you are screwed at this point. But I guess you never know for sure until you fire it up.

He's screwed.
Probably exhaust manifolds and heat exchanger.

The engine is a closed cooling system so the actual engine block/heads will be OK. The bad news is the exhaust manifolds, heat exchanger, oil cooler, power steering cooler and even the raw water pump may have problems. Its a shame because this engine is really easy to winterize, hopefully it wont be an expensive lesson.

How cold does it get inside the building? If the building is insulated it may not get that cold, the building I keep mine in stays at least 35 degrees in the coldest outside temps. I still winterize my boat though. Good luck/

springtime things will look like a Sprinkler under that hatch

I think it all depends on the temp inside the building.

I'd at least take the time to go winterize it. That way if it spews all over the place you know you ****ed and can spend the winter saving/looking for parts. If it doesn't then you might have saved it.

get one of those thermometers that records Hi and Low ..Radio shack has one that has inside and outside readings .....put the probe in the bilge and the therm outside the boat ....see what kind of readings you get .....is there power in the building? I put 3 150 watt bulbs in my 311 and the temp never got under 46 degrees ....with outisde temp of 27* .....

Use the hand air pump on the front of the motor to try and blow out the water system. If water is able to be pushed out then you may be safe, if not it's probably already frozen.

I am in Iowa and the lows have been well below zero. many days, the highs have been single digits. Something is going to be busted. Hopefully the closed cooling will save the engine block.