Sal Testa was rising through the ranks, and he feared a potential threat. Being that Testa's father was boss of the family, Salvie probably, more than likely held influence with some of the guys. I'm sure it was a bunch of good fellas who wanted Scarfo's egotistical ass clipped. Salvie coulda been boss if Scarfo hadn't knocked him off: Smart decision though for him as boss, if I must say so.