400 stroker

It's an excellent combo for street or strip and even more so in a Duster.

If you have the 400 block, bore it out if needed and only if needed.

IF you have a 440 crank, you could cut it down and have the mains fitted to the 400 block. This can be expensive to do.
Otherwise, you can purchase a brand new crank just for this stroker combo easy.

Pistons are off the shelf. An easy purchase from many companys.