odd stroker combo.

im planning a new engine for my duster drag car. this with be a a bracket motor in a 2720lbs w/me in it chassis car. know parts.Virgin 400 block, enderal bird catcher, indy tunnelram alcohol injection for induction. heads will be (for now) promaxx heads ported to max wedge intake. external twin line oiling. BCR mains/girdle system .Now im thinking 512 or 470 but with 1.122 ch pistons. the 470 would use a 6.86 rod leaving .043 for decking. the 512 will use 6.7 rod and leaves .033 for decking. whats you take? i know the pistons or short but it is just a bracket motor. should i be worried about the skirts coming to far out of the bore at bdc? what other issues could i be over locking.