Need information on my classic mustang!!!?
There are two Boss cars in that year, the 429 would be the most rare, followed by the Boss 302. The sportsroof might actually be more rare than the Mach, because the Mach wasn't too much more of an upgrade over the base sportsroof/fastback. The Boss cars are worth more, then the mach, then your sportsroof, based on desirability, however it also depends on condition, originality and options. If you want to speak to more Mustang owners, try the classic forums on stangnet.