I'm curious in what way you think a V8 version would be better or needed over the V10? The the HP from the V10 is nearly unmanageable except by a good driver. What it needed was a sophisticated traction control system with an on/off switch.
I think the V10 was cool and a V8 based on it would have made a neat motor. Not saying the Viper would have been better with a V8. Other than the sound, I struggle to enjoy the audio characteristics.
And I don't think it would be reasonable to spend the time or effort to cut one down either. A 408 with good heads would probably be comparable.
I just think it would have been a cool evolution of the Magnum to build an 8/10th Viper motor. Made no viable sense for Mopar to do it since they had absolutely nothing to put it in so not saying they missed the boat. Just daydreaming about what-if's.