need help on authenticating a 70 SS Nova

[69hurstSC]

hey guys. i ran across a 70 SS Nova and need some help authenticating it. i haven't seen the car as it is to far away to drop in for a visit. the things the seller told me over the phone is that its originally a 396/375, 4spd, 12 bolt dark green/black vinyl, black interior with a bench seat. the original block is gone. has another 396/375 for the car. is there SS 396 special equipment that i should look for? would the VIN help indicate anything? i will ask on a build sheet. how about under the hood stuff? i realize that this could easily be a SS clone and need as much help as possible (not good with GM). if this car is authentic is it worth $7,500 or should i run away now.