Kingpin's surface area is 3.22 m^2. 40% of that gives us his cross-sectional area or 1.288 m^2, 1 288 000 mm^2
Minimum elastic limit of steel is 170 MPa.
1288000*170 = 2.1896e8 N
He seems to deform the truck by his own depth. Human width is 10 inches to 12 inches, since Kingpin is thicc I'll say 12 inches at least or 30.48 cm. Displacement seems roughly that.
Also I'll multiply by 50% since not his whole body was smashed into the truck but half only.
2.1896e8*0.5*0.3048 = 3.3369504e7 Joules, 0.008 tons of TNT