OK, i'v got it. The transmission that I plan to use does not have the rods sticking out(came out of a 1974 Spider), so I should use the bell housing without the hole. Thanks for the information.
I am rebuilding a 101 spitcase transmission, and I do not have the reverse switch. I do have one from a 105 hydraulic transmission (early type with rods sticking into clutch area). However, if I install that switch in the 101 bell housing, it is not in line with the 5-R rod. Any thoughts how to solve this? Fabricate bracket? Source correct switch?Here is further clarification of what Ed just wrote. With the transmission in "N", if you have three shift rods poking out the back of the box, you MUST use the bellhousing with the hole to fit all three. In "N" these rods will all poke out the same amount. On later transmissions, this feature was changed, and the rods will be blocked by the casting. Using the later housing with the earlier box will not work.
In the pictures below, note the three rods through the hole by the back up switch. In "R", the reverse rod will move further out, activating the switch.