Rnaz, .815" more stroke then 3.31".
A good friend of mine ran 10.40's with a stock stroke 318" with spray. It can be done and has been done.
I like the idea of spareparts running a 318". Kinda cool if you ask me!
I spent more $$$ then spareparts to run 10's N/A with a small block. I wanted to run 10's, stay with a small block, and in my heavy car.