Revised Rule for 600R for the remaining 2013 Season

Engine Terms and Conditions

1. Restrictor Plates: ¾” restrictor plates must be positioned flat in each intake tract such that ALL air entering the engine MUST flow through the ¾” hole in the restrictor plate. No add-on inserts or devices designed to improve air flow thru the restrictor plate.  Plates may be positioned anywhere in the “Stack” (head, manifold, throttle body), as long as air flow meets the above criteria.