I measured mine at 7 inches directly forward of the "step" in the floor. and 16.75 to 17 inches from the inside edge of the base of the roll bar. The measurement from the rollbar is angled somewhat forward not directly toward the inside if that makes sense.
One of the most maddening thing about 1990s American cars is the mixture of metric and SAE fasteners throughout, as Detroit gradually shifted over to the standards system favored by Communists, criminals, and the morally bankrupt. -Murilee Martin