I cant give you any details about armed forces atm, but on political side:
Due to IB crisis and Tito-Stalin split at that time Yugoslavia was preparing and expecting possible Soviet invasion at any time. There was a lot of talk being done with western powers at that time.
But unlike Korea this scenario would mean Soviet and NATO troops shooting at each other directly, and that's something both sides would like to avoid.
So, if Soviets attack before Tito gets official NATO support there will be a lot of angry words said in Security Council but I don't think NATO would commit to fighting Soviets directly, on European soil.
OTOH, if Tito manages to get American support and maybe some symbolic troop deployment before Soviet invasion starts, it is very likely that Soviets won't attack.