well it not tottally screwed but if you are going to do it right the engine has to be pulled apart seals cranks inspected at a minimum inspect the bore ect and the 500 to 600 doller range is more in the range. I would not buy a blown motor for more than that cuz it will cost you that much more to have it torn apart to insure the motor is good to go if you just do the topend and you have a bad crank seal, bearing, you have just thrown away 300 bucks worth of pistons and bore. just my 2 sents