Right price to offer on a 69 big block GTS

So I just purchased a 68 340 4 speed GTS wich I've always wanted and just paid what the guy was asking lol. I've been doing all kinds of work to get this project going and then I get a call from the brother of the guy I bought the Gts off of. He wants to sell his 69 big block GTS wich was an original 4 speed car converted to auto. So this car has no engine or trans right now and needs small patches on the bottom quarters. Any idea what a fair price would be to offer him? I'd love to have it but I don't want to overspend on it.

Thanks!