The sideshifter is a 901 trans right?

yup....short answer

they make another 901/xx.....it turns the other way for ass draggers.

Good just bid on lot of shift forks and had a brain fart. I think that may have a broken one. If not I'm sure somebody here could use them.

The 914 tranny is 901 based, but I thought it was called a 904. Am I wrong?

904 was its own breed of box...

i ve heard them called 901's and 914 boxes

Both are similar, however, the "901", as Mike Z noted, was installed in the 911/912 and the "914" version was built for the mid engine installation which meant opposite rotation, different design for gear selection, and ears on the tail piece for mounting.

Bottom line: the type 914/xx transaxle is a type 901 transaxle derivative. Check out the numbers stamped on the underside rib of each type.

tailshifter = 914/11
914-6 = 914/01
sideshifter = 914/12
916 = 923/01

The 916 used a transaxle that was a derivitive of the 915 that was installed in the 911. It has the side shifter setup and the end cover that George Vellios copied for his 915 conversion parts.

a 923 trans is a one year only trans....76 912E's had em. 915 with 901 input shaft to meet the type 4 flywheel

Because the 916 never actually went into production, Porsche reused the 923 designation for the production 912E transmission. I "think" that the 912E had a 923/02 transmission.