If base power is 40, a critical hit in white is worth x3 making it 120, and because Throh is the only pokemon that can learn it it gets STAB, taking the power to 180.
Is that correct is basically what I'm asking?
You got it wrong. Critical hits are 2x, not 3x. So, it is:
40x1.5x2=120 power. It will have 120 power, with all the calculations.
The only way to make storm throw have a base power of 180 without any items is to skill swap the ability sniper to Throh which makes crit hits 3X the base power instead of 2X