Re: 1970 Original Owner Chevelle SS 396/350 HP speed
I would ask 15k and go from there. While a matching numbers 396 is nice (I had one and was dumb enough to let it go) it will not not bring the stupid money a LS6 car will, especially since it is a bench seat car with no A/C.
While you can veryify its an SS car since it is local to you, with known history, the next guy (and there is always a next guy) probably will not be able to. So you really need to find that build sheet because without proper documentation it is very hard to prove the car is an SS. You could get a BBC in a regular chevelle(although rare) so the presence of a BBC in the car doesn't prove anything and since you can't tell from the VIN or Trim Tag the car was an SS you really need documentation. Are the lower control arms boxed?
Find that build sheet or some other supporting documentation otherwise its a nice looking original car and you need to price it accordingly. You also need to verify the eng numbers and the partial VIN on by the oil filter. Same with the transmission. L34 cars were the most plentiful of all the SS's that year although that color combo is probably a little on the rare side. I am sure an internet search will turn up some useful data for you to use when considering this car.