I saw in SCMDraft that you can go bigger than 256x256 but I tried to play a map bigger than that and it didn't work. Is it possible to make a map bigger than 256x256 that plays, if so please let me know and what dimensions work.
Thanks.

Okay, so far, everybody knows that it's impossible, but I heard that an RPG (Pylon RPG) has been able to do so, but I never saw it... It's a rumor =o
So let's considere the answer is "No".

i seen 0x256 and 256x10

In short, not really.

I believe it crashes only if it's your first game, or maybe that was something else. Either way it's not worth it, since you can just control the field in which you play.

You would never need anything larger than 256x256.

Most 256x256 maps would work in 192x192. Starting a map that's 256x256 reduces your chances of ever actually finishing it. You can always change it to 256 later if you really need more room, but you wont.

Yeah I know this was more of a "what if" question, not only that but also think about max units.

You cannot make it any larger than 256 on any dimension, as the minimap of SC simply cannot support it. While you can make it almost any size smaller, SC can support smaller than 256, just not over 256.