Chevy 37, while I agree with Mike P., a Hemi is a Hemi. I would not let that 331 get away, especially if it's in decent condition and a reasonable price. In my opinion, a stock 331, 4bbl Hemi is cooler than the generic 500HP/350 or BBC. It would also be more reliable, and when you get to the show or cruise in, and people see that Hemi, the horsepower will not be an issue when it comes to the WOW factor , and Hot Hemi Heads has about anything you could need for the 331, 354, and 392.
Keep in mind, I'm an "older" hot rodder, and while I realllly LOVES me some big HP, it's not my number 1 priority anymore
Jack