Need some advice on what to do.

[fsstnotch]

About October of last year I sold the motor from my street stock to this person. Thinking he was a friend, I took his old stock motor, w/cracked water jacket, as trade because the buyer of my car had a stock motor rule. I was cool with accepting MONTHLY payments on the remainder of the balance on the motor which was $555. He didn't make a payment on it, didn't make a payment on it, and finally around January I started hounding him about it. Something I shouldn't have had to do if this guy was such a friend. Well, he kept saying, "I'll bring money to you!" for a couple months. I even offered to just give him the money he had paid back and take the motor back. He said, "no, no, no, I will bring you money! I promise the motor will not go into the car until it is paid for." So, fast forward a couple months, it's the start of racing season and this fool has still not paid a dime. Now, I am in Afghanistan, and I go on the Eriez website to find that he ran the car.... I text him and he tells me he ran it with my motor. So now I'm pissed that not only has he not paid a dime for the motor (just the money that the guy that bought my car put in my hand), but he has also ran my motor in his car after telling me there is no way that would happen. He tells me he will take my wife money for the motor. Ok, I'm cool again. they had talked and he agreed AGAIN that he would make monthly payments and that if he missed a payment, I had the right to seize MY property. He brought out $60 a couple weeks and a few badgering texts later, and ran the car the following week at Eriez... it was a ploom of blue smoke because the "dipstick" didn't put the dipstick/tube in it when he installed it in his car. Hasn't paid a dime since late may, early June. He texts me and says he will just return the motor. Great!!! Now we're getting somewhere! So I find a buyer for $500 to get the money HE owes me. Now he won't give it back..... Dude is a joke! Can't be trusted! (CLEARLY) He feels I owe HIM money! LOL For all I know, the motor is junk after he ran it with no dipstick tube, don't even want to know how he knew the right amount of oil was in the motor....

I understand $500 is pretty petty. But I will be getting my money or my motor just for principle. He thinks the whole situation is funny! So what is my best course of action? I was told if I send him a certified letter requesting my property by XXX date and the consequences of not returning my property that I have the right to take his entire racecar to get my property if I so choose. Anybody got an idea? If I have to, I will go back down to a stock next season when I'm home and I will put that fool in the wall every week! But I'd rather not.