The more cubes you have the better off you will be. Torque is king! My choice would be to build a 400 stroker, either 499 or 512 cubes. That is built using a 400 block and either a 4.15 stroke crank or a 4.25 stroke crank and 4.375 bore. 440 SOURCE has a lot of info that will help you understand what you are getting into. The big deal with strokers is they make so much torque down low you can build a 499 that will be a blast to drive and you can use 3.55 or even 3.23 gears, a mild cam, and a tight converter that feels like stock till you stand on it.
If you need to budget then go for big cubes and use a mild rate of lift cam that won't kill the stock pushrods and rockers. Older cam designs designed for chevs can do this and still make decent power.
There are also 383 stroker kits available from 440source. But keep in mind 383 blocks are weaker than 400 or 440 blocks. Don't be afraid to build a bb mopar. They are very simple and straight forward. Just aquire books and good measuring tools to check everything.