Hi buddy I've fixed the calc based on your observation.
Can it be used now?
Godzilla (Final Wars) lifting strength
vsbattles.fandom.com
Can it be used now?
Y = (11.655 / 0.28)^3 / 1000 = 72.121166 megatons
Divide by 2 since it's non-nuclear, and you get 72.121166 / 2 = 36.060583 megatons (City level)