The drive shaft cars and chain cars do not belong on the track together.
They are 2 totally different animals that happen to look similar but drive completely the opposite.
Chain cars are lighter, accelerate quicker and have to keep thier momentum up. They also have a lot more left side wieght giving them a better advantage on slick tracks.
Real midgets are slower out of the hole, have faster straightaway speed n scrub off more speed thru the corners.
But just because they turn similar lap times and need car count you throw them together.
It would be no different than throwing midgets and late models together because thier lap times are similar.
And yes that has come up at tracks we have run, we have been asked to run a exhibition race between late model fast time vs midget fast time.
So for you guys crying "integrity", you might wana chew on that thought for a bit.