Not real easy to say without seeing it firsthand. I'm not sure how much added value there is IF it's an original 426 64. My gut feel is more in the high $30's, maybe low $40's which I wouldnt pay that. In the $40's I would be looking at other Mopars
BUT more of a collector type buyer that's in need of a 64 might spend that.
Just my rookie opinion
I get a kick out of the 13 out of 18 claim. It only means that Galen has 18 in his registry and this one is the 13th one in the VIN sequence not that Plymouth only built 18 of them and his was number 13.