Im going to bake a coconut cake in an hour or so and need some quick advice.  Following the original WASC cake I replace the water with coconut milk..but how about the sour cream?  Does that stay???

http://cakecentral.com/b/recipe/the-original-wasc-cake-recipe

Also I'm making a tiny approx 6" cake, so how long should I bake for???

Seeing as you need urgent help I thought I would throw in my 2 cents. Disclaimer, I do not make WASC, but...

I would substitute coconut cream, you know the fatty part that floats to the top of the can of coconut milk, for the sour cream in the recipe.  Coconut milk and coconut cream are very fatty and thick which would make a better substitution for SC instead of for water. 

I imagine you could also use a coconut cake mix instead of a white cake mix, and coconut extract instead of vanilla.

HTH

That's a good tip, I shall try that  as I'm not a fan of sour cream. Thanks.