There was driver Dave Beyersdorf who used to run the ARRC and a lot of Waterford Hills and SCCA races up here around Michigan . He has since moved to the South East .
His crew chief Pat Shey used to build some very nice ducts that fit nicely and were very effective .
Pat was from the Toledo Ohio area if I remember correctly .
Sorry I don't have any contact for him but Dave is on facebook . You might be able to look him up .