"Mario Andretti drove Joe Leonard's #60 STP Turbine in the 1968 "Rex Mays 300".  I bet the picture of #60 was taken during practice, with Joe shaking down the car.  Mario usually sat pretty low in his cockpits,  not so in this picture. 

The results for the race.

Note:  Mario's original car retired and he took over Leonard's car and pretty much immediately crashed with Pollard!  It would be a rare photo that caught Mario at the wheel of this car!

Mario used a light colored helmet: Tremblant 1967, and Labatt Indy 200 1968.

The Pratt&Whitney turbine in the Lotus 56 was used in helicopters and stationary power supplies.  As an engineer,  I always wonder how they dealt with turbine lag.  And Indy, and on ovals,  this might be controllable.  But on road courses I imagine you needed to use the brakes in corners to 'wind-up' the engine.

I saw these cars race in Milwaukee.  They qualified well,  but got jumped at the start.  In the 200 mile race, early domination disappeared,  and retirement was from 'brake failure'.

Cutaway of Lotus 56."