I'm looking at a boat that flipped over and the engine was submerged in fresh water and has had water in the engine for 4 months. Is the engine salvageable? The hull and interior still looks good, is there anything else to be concerned about?

4 months! It's toast.
If they didn't take care to pickle the engine they probably didn't do much to the rest of the boat. Expect ALL electrical will need replacing. The hydraulics and drive may have water in them too. Also check the stringers, transom, floor for rot.
Gary

Would the fuel injection be toast or just the internals, would it be cheaper to buy a new 496HO or rebuild this one assumeing the labor is free? It also has a procharger, any chance it is OK?

The electronics and the engine accessories (starter, alternater,ect.) are all shot.

RUN, FORREST, RUN !!!!

Trim motors guages, wiring....THe list goes on & on....

If you are to seriously attempt this project, in my opinion, the best course of action for you would be to look for a complete bobtail motor. That will fix the motor, but I don't know where to begin about the rest of the boat. You could be in for a world of trouble.

the wiring will be shot and rewiring a boat is a pain in the ass. Not very difficult just a major hassle.

Believe it or not, I did the deal like this on Fred's Sonic. Other than new starters, alternators, rebuild engines most everything else you can buy used or rebuild. Trim pumps & trim cylinders, k-plane pumps & rams are rebuildable with Merc kits... easy to do. But everything must be flushed very well. Look on ebay for wiring harnessess. I just bought two 20' Merc engine cables for $50.00 each ( cost over $300.00 each). Solenoids u can used Ford units. Just like the Merc and only $6.00.

It does as Puder said, take a long time. I have taken a year to do mine, but could only work weekends & vacations. It's gotta be a labor of love.... and a hell of a good price to boot!!
Good luck.

Alt, starter, trim pumps will all need to go to rebuild shop.

Throw the longblock away, the distributor (if it has one) away, the fuel pump away.

The fuel pickups may be corroded in the tanks.
The injector rail will be okay but plan on tossing the injectors.

The ECU is a goner.

PS pump may be salvageable.

Gauges gone.

it better be a free boat.

I've sunk several. The main main mainest thing is to immediately change fluids and get them running as soon as they come back up. Amazingly, a boat is better off to spend a few extra hours underwater, than it is to come up and sit those same few hours.

i sank a 27 eliminator daytona w/blower motors and it was down for 2 days. we got it out and pickled those engines and they ran great. i just freshened them last year and put them in my 32 skater and i would say they run better after they were in the ohio river for 2 days