The GR700, GR700A, GR1000, GR1000A, and GR1000F transmission kits are variations using the Tremec T56 Magnum h-pattern transmission, which is the highest torque rated 6-Speed manual factory transmission ever built. The GR700A is the aluminum bellhousing kit, hence the "A" for aluminum at the end of the name. The kits without the "A" use the quicktime steel bellhousing.
The magnum transmission is heavier duty than the older Fbody T56, and while they share the some of the same parts internally as the TR6060 the case is not the same. The Magnum does not come from the factory with a bellhousing, as it is engineered to be adapted onto many engine combinations. Most TR6060's are engine specific, and they have a bellhousing that is not easily removed since it also contains the input shaft bearing support in the bell.
Check out the technical section for install guides and pointers.
Got something unique or different?
Check out the Universal kits above. I can put together a universal kit with a Magnum, Magnum-F or even the Magnum XL. I can put together a "universal" kit for many different cars and engine combinations. Use my Quote form to get a quick turnaround estimate!