Should I call it quits?

Didn't the V8 cars in 70 get 8 3/4 axles?
What's the 5th digit of your VIN? Should be G if its a 318 car.
How do the grille and dash look?

Only the 318, 3spd manual cars got the 8 3/4 rear as far as i know. And of course the 340's.