I believe the basic rules, besides safety ones, are that all blown dragsters must run automatic style transmissions, no lencos. I think that they recently allowed 14-71 blowers on big blocks and 10-71's on small blocks. Altereds pretty much have no limitations. Really the main thing to slow the cars down is the fact that it is a dial in, break out class and having the fastest car does mean a whole lot. The IHRA does not even run any quick 8 shootouts anymore so most of the drivers want to just make sure they are quick enough to qualify yet be consistent on race day.