Pro-stock now days are pretty aerodynamic. The forward facing scoops supposedly actually create a couple PSI of positive pressure (above atmospheric), kind of like a little mini-power adder.
Salt Flats would be cool, but again, those motors only run 6-ish seconds at a time. Im not sure they'd last on the flats, with the kind of RPM they turn and the crazy valve spring pressures they run.
I think it would be very interesting. As you know, F1 their aero is set up for max downforce. High rpm engines. Tracks are set up for cornering, braking, tires, not straight speed.
So, technically, they would top out quicker than a Pro Stock car on the Salt flats, due to the aero pushing the car down, and increasing drag.
Cars like the old GT1 class cars from the late 90s (911 GT1, Mclaren F1 GTR Longtail, Mercedes CLK GTR)
would do well, with their flat bottoms, longish designs, they were built for top speed, but their wings would create drag...and then there is the gearing...
it would be a unique experience to see all these classes on The flats, with the bugs worked out with gearing, engines as you said.