1970 challenger 340 6 pack TA

This is a once in lifetime opportunity.
If the serial number on the car and motor match and are that of a T/A, I wouldnt even hesitate an offer.
Take $25,000 cash with you and lay $20 k on the table after you chat him up for a while. Sounds like his life has changed and he probably has his mind on others things now.
CASH TALKS!!!!

Would also love to see more pictures.

I agree with taking $25K in your pocket but may even lay less on the table up front being he is a Chevy guy. I would make sure to look for the VIN# on the block above the oil pan rail first. If it matches pick a day where the weather is crappy (changes sellers mood sometimes) and put $15K cash on the table making sure he knows you have more so he doesn't get frustrated. If he gets excited start talking about the things that aren't right or are a major concern....go from there.

I personally would not have an issue paying $25K for that car if the numbers match. My problem would be not being able to see it in person like you have and getting it back close to the Great White North.