[X-TECH MAN]

When I worked for IHRA in the 70's they had thier own class guide. As the years passed by and IHRA was sold several times they just used the NHRA guide. Then as some of the HP factors we noticably out of wack IHRA made some changes slightly different than NHRA's. As far as the production S/S cars are concerened IHRA had a guide that contained the lighest car shipping weights for that part of a seperate S/S catagory called "Formula S/S" as car counts decreased over the years they were combined into regular S/S eliminator based on cubic inches to shipping wts. Now you have "Production S/S" (same class structure) and they just use the lighest shipping wt listed in the NHRA guide per cubic inch to obtain the class. Along the way the multi carbed cars in the old formula S/S were discontinued. Now before someone wonders what a "Bastard" class Production S/S is....its a take off on the old AHRA formula S/S cars (cubic inches to factory shipping wt) only they look much better today and not much different than single carbed modifed cars running in NHRA.....lol.