Originally Posted by MrChevyDC3
What would you consider a "decent amount of nitrous"? I have a 150/250 dual stage NOS kit, and I plan on spraying the 150. I'll have an msd electronic retard box, and I'll run 110 octane at the track when I plan to spray. The motor is a 4 bolt main OEM.
Using the KB info as an example, a NA engine w/a 4.030" bore might use a top ring gap of 0.0065" per inch of bore diameter. For street nitrous use, this factor is increased to 0.008"/in. I'd consider a 150 HP shot as being "street" nitrous use. That said, it is always a good idea to consult w/the manufacturer on such things. They are in a better position to recommend exact specs. Piston to wall clearances are sometimes opened up slightly (half a thou, so not talking much) at the street nitrous level, again- consult the manufacturer.
BTW, current thinking among many top flight engine builders has the second ring gap ~ 40% wider
than the top ring. Ex. 0.016" top/0.022" second. So you might want to research this as well.