i dont recommend a C6 it prolly wont fit in a 70 with out cutting the tunnel back plus c6 robs power and is HEAVY and you would need a new trans crossmember and shorten driveshaft a c4 can be built to withstand ANY HP numbers you have plus its lighter and smaller
Eddie1975 is right. The C6 will not fit without major modifications to the transmission tunnel. The C6 is 50 pounds heavier and takes about 25 more hp to run than the C4. The C4 can be built to handle over 1000 HP and is currently being used behind the bigblocks with special bellhousings. There is no need to use the C6 in a Maverick or Comet.