Don't think of them as Ford stripes, think of them as Shelby stripes, since he was a friend of Lutz and had a hand in developing the original Viper and the GTS Coupe prototype.
Actually, they are neither Chevy, Ford or Shelby stripes. They are "American" stripes.
Way back in the day - like pre WW2 - country colours were assigned to the nation from whence a car emanated for international competition; this is where we get 'British Racing Green' , Italian Racing Red, the German Silver, French Racing Blue etc etc. America was assigned White with blue frame rails. [as an aside, America was originally assigned red, but there were no [or next to no] active American cars racing in Europe or International competitions and the Italians decided they liked red better than whatever hue they had originally been assigned, so they just took it. No Americans were there to complain, so...]
After the war, no cars had visible frame rails any more, so when American cars - or American entered ones - appeared in Europe, they were White and the 'frame rail' paint was 'moved up' to stripes. Various people claim to have 'invented' the stripe package, but the first examples of any note to the best of my knowledge were the Cunningham cars at LeMans in 53.
Cunningham entries included Cadillacs, Corvettes, jags, Maseratis and of course Cunninghams over the years.
Sports cars began to move away from international colour recognition by the early 60s to a degree, but it was part of the rule book for Formula 1 until the 68 season and stayed basically true. Of course, 68 came with big corporate sponsorship and thus began the decline of the sport...