How much would it take someone to offer you to hand over the keys to your truck? Ya know, you're at a gas station and someone offers "x" dollars for your truck, which may be different than what its worth or what you could actually sell it for (though I've seen some craigslist ads for the make me sell it price)
Anyways, I'd start to think about selling my '68 for about $50k.....I don't have that much actual money into it, but the 3+ years of work get it pretty close if I value my time. Not to mention all the memories
My '69 I might let go for about $5k. On the other hand I think my wife would let it go for free