Don the pink and white car looks like a Monogram Kurtis K body. That was like PC 18 or something, a really early Monogram kit, but that was a glue kit, not a snaptite.
I think I have one of the early kits that had a yellow car on the front. The Kurtis is slightly larger than the Watson. Kurtis always kind of thought "the Head",Watsons nickname, stole his design. As everybody knows race car designs don't get stolen they get improved and that was the deal with the Kurtis and the Watson. There were vac bodies made of both those cars. The Watsons available today are excellent.,
The Strom Dirt Tracker was a Champ car andthe design was called an upright car after the Kurtis and Watsons hit the track. There is a fantastic copy of that body available from Big Donkey Resins complete with all trim except windshields, which are not hard t make, can be vac formed if you know anybody good at that.
The Eldon Watson and Lotus 38 are actually both 1/24 scale cars, they used the nylon chassis, but they were 1/24 cars. They were sold in the clear cases but that pair of cars was also in a race set they sold called the Indianapolis 500 set, I believe. Both those cars were pretty good and the Lotus also can be detailed nicely.
This is the Big Donkey Dirt track copy. The whole kit is under $30. Indycals has decals for a few versions of this car
this pic is the Dirt tracker and the 51 Indy winner, the Belond Special. I made the Belond which is a Frank Kurtis design from several of the Monogram PC18 Midget kits. I cut and sectioned and bondoed till I got the same outline as Klindists scale drawing, but I left the body wider so a chassis would fit easier and it would still be a competitive car.
There were appx 35 Watsons built but they got sold and repainted about every year.. Kuzma, Kurtis and other builders also copied them pretty accurately.