I used to watch Speed Racer all the time when I was a kid. I don't know what your talking about "mach 7" thing. I know the Mach 5 is the car Speed drives in the old show because thats the fifth mach up of the race car his dad pops build. Where the mach 7 comes to play at ???? don't know. I saw that model also.
Ive seen the new show and have mixed feeling for it. I not 100% sure I like it....
Scott