All 200, 229 and 262 cranks are INTERNALLY balanced; So, you can use any small block flexplate(the 229 is good) that is not balanced---except for the 400's. This is according to the 90 chevrolet power manual chapter 4, pg 19. i know it's not real current but all those engines were produced before 90 and the thus info is still correct regardless.
Good luck and go for it; i'm leaning towards this engine for hi-po work believe it or not.
P.S. correction---the correct term is semi-even fire for the 200 and 229 because cylinder firings happen at 132 degrees, 108 degrees, 132, 108 and so on. The 262/4.3 is even fire because firings happen each 120 degrees---you probably already knew that. And the odd fire is the hardcore common pin crank for hi-po work---150, 90, 150, 90 etc. firings.
Last edited by against all odds; 01-14-2012 at 04:25 PM.