A 318/340/360 distributor will not just drop into a 330 DeSoto, the shaft isn't the right length. Hot heads does make an adaptor. All of the early hemi's can use an LA distributor with shaft length adapters, except the 241/270 dodge, it's actually a direct fit for those. All the early hemi's have the same bell housing bolt pattern for transmissions except for the '51-'54 long bell Chrysler 331's. The rest can all use the same adapters.
As far as negative, I'm not trying to be. I love old Hemi's, I actually own 4. Two Chrysler 331's, a 291 DeSoto, and a 315 Dodge. But, they have drawbacks too. They're seriously heavy, and pretty expensive to build. They can be built on the cheap if you're not looking for a lot of power (most had a stock compression ratio around 7:1), but even then they will cost more to build than a small or big block. As a showpiece they're beautiful, but as someone mentioned, it's easier and cheaper to build a small block stroker. You'd probably make more HP, and be lighter. But, nothing sounds or looks like a Hemi. One of mine is going in a '37 dodge truck, another one may end up in one of my '53 dodge trucks. And of course some extra's just in case :D .
I personally think they're better suited for hot rods, you can run sans hood sides (or minus hood entirely). Plus it seems a little strange to me to put a '50's engine in a late 60's or early 70's car. I also like my muscle cars to handle better than they would with a big chunk of Hemi up front. But that's just me. I also think the projects already posted here are awesome!
Still missed a few...
Dodge had a 241, 270, 315, and a 325
Chrysler had the 331, 354, 392
DeSoto had a 276, 291, 330, 341, and 345
And there were a few different "poly" blocks with varying displacements that can be converted with a head swap. The Chrysler 301 was one, there were a couple others with displacements not already listed.