Cars with blown motors just do not sell. I've been watching some on CL for months and they do not move (think I saw the one you are talking about a week or so ago on CL).
Unless you've got a trailer to hand you'll have to get it towed so extra cost there. Basically you have to persuade the owner that it's not gonna sell so let you have it dirt cheap or be stuck with it. t won't sell at that price.
Offer 500, if he says no, leave number. If he calls back he's desperate so drop to 400 (you can always go back up a bit).
Anything I might say is probably worth what you paid for it, so treat it accordingly!