in a short hemco's website sucks. I need a hemco plenum that has the opening on the bottom much smaller than the stock/precision plenums. The throttle body opening must be the one intended for a 70 mm throttle valve. I don't know if this is specific to the race version or not. If the stock appearing one came with the larger opening I would prefer that one. the 3rd set of pics down on the link are of what I'm describing
http://www.gnttype.org/techarea/pictureguides/intakes/customstgII.html
http://www.gnttype.org/techarea/pictureguides/intakes/customstgII.html