At this point, I kind of miss Don Moore complaining about tire companies........
Once again, there are two main factors working against your idea. One is supply equals demand and the other is risk versus reward. However, there are several other problems with this particular idea.
If there was a bigger demand from the fans for more Silver Crown races, there would be a bigger supply. If every time a promoter put on a SC race, he made money hand over fist there would be more Silver Crown races. If there were 50+ cars at every track and the promoter could count on a big back gate, there would be more SC races. Except for some "traditional" dates, the crowd that a SC race will draw is very suspect. Also, except for the few "traditional" dates, the car count for a SC race is very suspect. Also, the fan base for a SC crown race is a niche group in a niche sport which translates into a very small population. Promoters will book shows that make money. As much as modifieds get railed against on this board, there is a reason that promoters are always creating special shows for them. There are a lot of them. There are a lot of drivers, and they usually have a lot of fans. Why are there not a lot of SC shows? A lack of cars, a lack of drivers and a lack of fans.
When the average fan has to determine their "must see" races for the year, a SC race usually is not on the list. Start with a simple head to head completion. Would the average fan rather watch a SC race or a USAC sprint car race? A SC race or a midget race? I would even say a SC race or a WOO race? I think for the vast majority of people the SC races looses every head to head battle.
Finally, back to your original question. You stated that you would have plenty of cars. My question is how many competitive cars are actually still out there? It is not like these cars are raced all of the time. As someone else posted, what is your ticket price for this event? Go back to my first point, there is not a big demand for a SC race. Ask the average fan if they would rather go to 3 non sanctioned wingless shows, 2 USAC sprint car shows, or one SC show? Which one are they picking? Finally, you stated that you would have plenty of drivers. Where are these drivers coming from? As the SC fields become smaller and smaller, the number of experienced drivers becomes smaller and smaller.
Unless you grew up with the tradition of the SC cars, it is hard to become a fan of them.