Ok, so if anyone really wants to know... I just grabbed the info for a random year. 2007.
https://www.edmunds.com/lexus/gx-470/2007/features-specs/
https://www.edmunds.com/toyota/4runner/2007/features-specs/
Not like the debate will end, but it will make liars out of a lot of people. A cursory glance at the 2019 specs show the 4Runner is wider and longer, but the GX is taller and heavier.
Dimensions/Weights, followed by the Lexus GX470, then the Toyota 4Runner Limited V8.
Front Leg Room: 41.8" | 41.8"
Head Room: 40.2" | 39.7"
Shoulder Room: 57.5" | 58.0"
Hip Room: 55.1" | 55.3"
Rear Leg Room: 36.8" | 34.6"
Rear Head Room: 40.0" | 39.1"
Rear Shoulder Room: 57.4" | 57.2"
Rear Hip Room: 54.8" | 55.4"
Weight: 4871# | 4530#
Track Width: 62.2" | 62.2"
Length: 188.2" | 189.2"
Width: 74" | 75.2"
Height: 74.6" | 71.1"
Wheelbase: 109.8" | 109.8"
Ground Clearance: 8.3" | 9.1"