If you already have a 383 block and can’t easily get a 400 block, use the 383.
I have a 383 .030 with a 440source stroker kit. Makes 489 cubes. Mine has flat top pistons
and will be 11-1 with Ported Edelbrock heads. Comp XR292R solid roller and a tunnel ram with dual carbs.
I bought the unassembled short block off Greg’s list, 4.25 stroke 6.535 rod, 440source kit. I thought about getting
a 400 block and getting new pistons but decided to use what I have. If your starting from scratch, then start with a 400.
Your most likely going to want to use a dished piston.
http://store.440source.com/Stroker-Kits/products/3/ Good luck.