Draco;
There is one important thing to consider with a 9" solid rear, that is the driveshaft length and U-joint bind on a real short driveshaft. Seeing as the 6 speed is longer , the 5 speed is a better choice. Cars with an independent rear don't worry about the up and down U-joint bind angles. The other option is to move the engine farther forward to make a longer drivershaft.
Good Luck,
Perry.
