I would think they came in both manual and auto, though I KNOW it's going to be weak as hell. lol
Even if it is a Mach 1 (which they did make in 77) the main problem w/ 70's stangs is they got weaker every year, as the enviornmental restrictions got piled on
(and it can be hard to find parts for them sometimes)
I actually have a 72 Mach 1, and even w/ the 351C like mine. it only put out around 170 HP stock!!! I basically had to modify mine to get comfortable/respectable HP for such a heavy car.
73 was worse, and then came the Mustang 2,lol
only plus side for the M2's is the 74-78 being basically pintos were really light compared to 71-73 so they didn't need quite as much HP. Which may be a good thing since the 302 in 77 only put out around 134HP