Not Buick Specific but I seem to remember Global West, with all their componants, had a 67ish Tempest that pulled nearly, or even 1.0G on the skidpad. That was with all of their componants, though. I would imagine low .70 or even high .60 in completely stock trim.
If someone can tell me how to setup the skidpad I would try it with my GSX. It has the global west front suspsension. Mark
im not really sure how to make one but you can make a contraption or you can buy an electronic gadget that will measure it for you i think they can also measure things like 0-60 and 60-0 and calc hp and torqe