I did some research.
The Allison car was made from real MPC dealer promos, taken apart and modified by adding a roll cage and ripping out the passenger seat. Chassis was painted black, body red and gold. Decal number sheets are custom. Sponsor decals are from the Isaac Daytona model!
"Allison" sticker applied over the original promo box.
There are groups that look for this car: Coca Cola collectors, Mopar fans, Charger fans, Allison fans and guys that just collect rare promo cars.
I know that a 1971 purple Charger promo can bring 700+ if mint and in the original box. This Allison coke car is priced a bit high, but the guy will negotiate since it states "or best offer".
The signature on the box is icing on the cake. That, IMO, places the car higher up the desirability list. Bobby Allison didn't sign a lot of stuff, like Richard Petty did.
