How much would a 1970 plymouth hemi cuda cost?

That really depends. First condition is everything! Then what features it has other then just the hemi! In all there is then the AAR cars that Mopar built that is far more expensive then the standard Hemi Cuda. Basically there is a lot of differences between packages, and features offered. Say the car has a floor shifted manual transmission, does it have the pistol grip shifter, or has it been changed to a normal "T" handled shifter. Pistol grips can be different too. Another feature some Cuda's had was a Tachometer that was also a clock. Condition wise you might find a Number 1 car selling for as little as $1000. Where a Condition 5 car selling for $20,000 or more (Condition 5 being the best condition). I have seen people try to get top dollar out of Condition 1 cars that are far below even that condition. A Condition 1 vehicle is usually a running vehicle that is basically the worst of the worst. Then too is the Hemi "original" to the car? Some guys claim to have "matching numbers" vehicles but after a little investigation the numbers don't match (i.e. the motor is a 1974 RV motor in a 1970 Cuda body, that originally was equipped with a small block). So you can see your question is kind of vague, sort of.