A "Spirit of '76" is different from a "True Spirit" truck.
As far as I know all Spirit of '76 trucks were 2WD long bed straight box sides.
All were painted white with patriotic star stripes running down the sides and '76 stickers.Low buck trucks with most probably if not all having a /6 engine.This was a factory decal package to commemorate the bi-centennial year and I would assume could be purchased from any dealer.I don't know if it is possible to find out how many were actually produced,but while not as flashy as some of the other trucks,these are still pretty neat and still worth saving.I 've had a lead on one about an hour or so away from me sitting in a JY,if it's in any shape at all,it will be coming home with me.
I really have no ideal if there are any codes on the core tag to I.D. one for sure,but if there is anything left still visible of the original decals there should be no way to mistake it.

Anyone have good pictures of one ?
Now a 'True Spirit' truck...thats an entirely different story...
