I know the car's been good to you, but you've got a $600 car there. You could buy a low miles cavalier for the price of the new motor. Or go to a used Cobalt that has a newer, better version of the motor for not much more. The best thing to do is nothing and drive it until the wheels fall off. That or sell it and get something with lower miles. I wouldn't even stick a junkyard motor in that car. Its nothing against the car, I'm sure its been great it just doesn't have any value and with a brand new motor wouldn't have much more value. If you converted to carb. it would cost you something and would likely lower the value even more.