Internally Balance Cast Crank?

Curious, can you mix and match cast cranks,3.58" throw with forged flat top pistons in a 340 with H rods, and get away without balanceing it? Would it be coincided internal or external balance?
Hey do yourself a big favor and get any combination balanced. I have seen your comments about this subject in other threads and the only way to do it right is to get the components balanced when ever you change anything. Got it? If you want to throw it together in your barn with what ever and however then go for it but don't waste our time with questions.