'71 Duster 440 or 360? Pros and cons

it's going to cost a ton of money to rebuild the 440 adn 727 and get it installed. first let me say this, there is no better hotrod than a bigblockdart, period. this being your first time attempting to install a rb into an a-body it's going to be a patience trying ordeal. please take note of the amount of hair you have before you try it because you will have less afterwards.
this is what i'd recomend, set the 440 and 727 over in the corner and rebuild the 360 and start driving it. we're talking fun here. after that is taking place rebuild the 440 and 727 to pretty good horse power that you want. start collecting all the other parts you're going to need to get it installed. find a rolling a-body drag car and put it into it and then start having some eyeball popping fun at the drag strip.

I agree regarding using the 360 first, and don't put much into it. Stock rebuild with a slightly hotter cam, like the 340 automatic grind or similar. Keep it mild and drivable.

About buying another car to do only drag racing...only if you have tons of room to store everything securely, and the spare money and free time to focus on two cars. And a truck and trailer to haul the car to the strip. Otherwise build the 440/727 combo for a swap in the future. 440 A-body on the street is a lot of fun, and damn quick.