Sounds like this has been strung out way to long.
Have you kept your emails and messages that he's said he's willing to pay you back? I would assume that if this has to go to court, those will stand as an admission of guilt and be a strong leverage point towards your case.
You may want to approach this in a different way now as I think everyone will agree that you've been fair.
1. Tell him that you need at least half of the payment by next Saturday. He's already missed his payment deadline and any bank in the world would demand the balance in full. You are not a bank and you understand his financial situation but you are at a spot that he's lost credibility with you. No more Mr. Niceguy.
2. Do not threaten him however make it known that if payment is not received, you are prepared to provide negative feedback on him at the various Buick group websites (V8Buick / 65GS.com etc..) Leaving negative feedback is within your rights and is actually an expected responsibility to warn others to use caution when dealing with someone. Again.. be prepared to use excerpts from the messages and emails he's sent you to prove you've been more than fair. Make sure not to threaten him with this as it could be perceived as both personal and as a form of blackmail.
3. Make your intentions of filing a small claims case on him known if payment is not received. Make sure he understands that any court or other related costs will be part of the court case.
As an option, you may want to offer him a way out by sending you a correct boxed GS frame in excellent condition at his shipping expense. From what I understand, he has several A body cars and may have the frame you are needing sitting around there someplace. This would make things right to you and he could find a replacement later when he's back on his feet (there are plenty of frames out there). I would only do this with a reasonable deadline for the frame to arrive on my drive and he would need to provide tracking numbers and carrier information after he claimed it was picked up.
If all else fails, be prepared to follow through with the negative feedback and court action and don't contact him until everything is settled through the court system. After you file, it's up to them to handle it and you'll see him and get to plead your side in court.
Many of us are sorry to see everything go this way... but right is right and we are all are expected to do the right thing in this hobby even in rough times.
Best of luck and please keep us up to date until this unfortunately has to go to court.
Chris
