ORIGINAL: jeffie8696
Sig has Kavan nylon props but the smallest is a 6X4. However you can get it in either nylon or glass filled.
Too much prop for these engines IMHO, esp for pylon racing. A 6x4 lugs Cox .049s down pretty good. Yeah some guys run them for this and that, but they really hold the engines back, and any time I ran a 6x4 on an .049 the results were never an improvement over a 6-3 or smaller.
MJD