Did you know there were 3 different 6-wheeled F1 cars? All Three Six-Wheeled F1 Cars To Gather For First Time at Goodwood (MotorAuthority.com) Read the rest at Motor Authority
Actually there are four...add the Ferrari 312T6 I believe they just converted the 312T2 to the 4 wheel configuration in the rear, so there is probably nothing that remains of it for Goodwood. Niki Lauda and Carlos Reutemann both tested it and after Reutemann crashed, they deemed it a failure...not to mention the width far exceeded the rules at the time.
I forgot about the Ferrari...the least creative solution and most forgettable of the three IMO. I wish the March and/or Williams had actually made it to the grid.