the truck came with manual or power brakes.the power brake unit was different betweenthose that had speed control and those without .power master cylinder is different than manual. vin # starting with F15 is a F 150 2x4 truck .the next letter ids the engine B OR K = 300 CID 6 , G = 302 CID 8 , H = =351 -8, S= 400 - 8 ,AND A=460 CID 8 CYL .