It's true that 100LL has lower density than most pump fuels. However that is also true of many race fuels.
Temperature plays a role in density specs but here's some published numbers to give some idea of the variations.
Specific gravities
100LL, 0.714 to .719
Pump Gas .74 typical
Sunoco GT .734
Sunoco GTX .764
Sunoco Standard .729
VP Vintage leaded .715
VP C9 .718
VP Blaze 100 .746

Race fuel info came from Sunoco Race Fuels and VP websites.
Pump Gas came from CRC E67 fuel Study (Durbin et al) and similar sources.
Av Gas from Fuel Mfc. Bulletins eg. Shell Au 100LL pdf

Distilation curve falls between typical street fuels and the race fuels I looked at. Posted a graph here:
https://www.tapatalk.com/groups/racingfu...579.html#p12657