engine seized?

[dory24]

here we go again. i have a crusader classic 5.7 liter with a holley 600 carb. got her in a few weeks ago and was running a lil crappy in the driveway and so so when i ran her down to the dock last week. drained 85 gallons of old fuel from her new filter/separator cleaned carb and ran seafoam thru it for a lil while. still running like crap, surging on idle and low idle stalls. went to rewire trim tabs this morning and figured id turn it over to see if how it was running. went to turn it over and backfire out of the carb then nothing. tried turning it over real quick once more and now seized, the starter engages but engine wont turn. yes i do believe im screwed. had to walk away before i did bodily harm to myself. any ideas before i spend a ton of money i dont have? ill try turning it gently with a bar later but it doesnt look good.