Sunoco 260 GT is an oxygenated (E10) fuel.
https://www.sunocoracefuels.com/fuel/260-gt
There's not really enough info to accurately draw a distillation curve but the three points show much flatter - typical of racing fuels.

100LL Av Gas is a low lead fuel with distilation curve closer to pump gas.
BP had more distillation points for their 100LL, so that fills out the picture a little better.