Hadn't read this one in quite some time. It didn't even look familiar. As written and when written the intent was to eliminate starting a race with one car and for whatever reason (damage or performance gain) replacing the car during a race. Racers must race the same car through his or her's entire set of heats that make up any one race. The car could be repaired if damaged but not replaced with another car. As far as a racer racing "multiple entries" they may do so but each car would be separate, individual "entries" and each car must be raced in ALL the heats that make up the "race". To do so a racer would have to be entered into the race line up more than once (i.e. 2 car entries the racer would be listed in the running order twice, with each entry noting the particular car number).
To date I can not recall anyone wishing to race more than one entry. One example that comes to mind would be if a racer was working on building and setting up two different cars for a particular class. The racer could enter both cars and get an accurate comparison of their performance.
So the short answer for Monte's "friend" is NO. Although I will say I have never been very firm on rule enforcement except in the case of a win, or when it came to Point races.
In response to Mitch's comment: "It appears to be written this way, but I believe in discussion the switching of cars between heats actually resulted in DNF but you were allowed to continue to participate with another car. "
Yes. If you switch cars in the middle of a race (during any of the heats making up any one race) you will not be credited with a "win". The switching of cars results in a "N/C" (Non-Compliant to Rules) as I would commonly list them. In the case of non-point series races, in any finishing position other than First Place, I would many times just ignore the infraction. My bad....