Josh, I suppose the car count depends on do you want to put original Race Hemi cars in the preferred spots, limit it to the original 1964 Hemi cars (how many did they make, ~100?), and there is a variable of how much the event is promoted to get the guys to show up with their cars? They had several tents at the 2008 reunion, probably 50-75 cars under them, about 10-15 AFX/AWB cars in the barn, and several hundred cars scattered on both sides of the track.

I can see how you could spend $100k hosting an event given the track rental costs. Maybe the Quaker City track was half the price Indy charges, but that still is a chunk of change for a stand alone event to break even. I haven't made one of your Monster Mopar events, but I'm guessing you already get a decent amount of Hemi cars already. Maybe figure on 100 additional original Race Hemi cars (all years) as a starting point. Maybe you need to have people reserve early to get a prime spot for their cars so you will have a better estimate a couple of months out from the event?