$ to bid on 69 Mach1?

[btr]

I looked at a 69 mach 1 today. The owners are dead, and it's going to the highest bidder. It has the shaker hood with 'Cobra jet' emblems and is an 'R' code ram air. It has a big motor in it, but how do I tell if it is the 428? I couldn't find any numbers on it. It looked as if it has been redone, and another guy there heard that it was a 390. It has a Holley carb with the #1850 on it. The motor hasn't been started in over two years and there was no battery to try it. The windshield is cracked. There are lots of little dents, but no major body damage. A magnet stuck everywhere I put it. There was no visible rust underneath. The tires are shot and the rims are aftermarket and probably need to be replaced. The dash has a few cracks, otherwise the interior is pretty good. It does stink like stale air and mice. It has traction bars, so I'm sure it was run. There is no rear or front spoiler.

What's a bid that is a 'good deal' for me?