I may be wrong, but it looks look a welder with Oxy/Acetylene tanks, a floor jack, one pit crew member with an air impact wrench, and 3 guys loading fuel into the trunk gas cap filler.
I think it's a classy look to have the fuel barrels in the car colors too.
This was at Lime Rock according to the gallery of photos it's mixed in with
http://gwadagone.fotki.com/trans-am-racing1966/?view=roll#206