Let's be honest....

I put a 5.7 stroker built by Tony Bischoff in my 70 Duster drag car almost 2 years ago. It has a Mopar drag pak manifold and a 1050 Holley Dominator on top of it, for drag racing only. I went with the carb because it made the conversion much cheaper, and I am a tight ***! :-)
Why the Hemi instead of a big block? Much lighter in weight. The car weighs 2800lbs. So far the car has been very consistent at the track. The only reason it doesn't win more is driver error!
Things I would have done different:
1. If you want to do 12.5:1 compression like my motor, do some research 1st on spark plugs. I waited until AFTER the motor was built to discover there's not much out there with a cold enough heat range for that compression ratio. I run Brisk ER12S and they do just fine and last forever.
2. If you want to run a motor plate, you need a truck front cover, again, didn't realize that until after the motor was built.
3. The only headers available for the swap will still require that you apply some "adjustments" with a hammer. :-(