doubling t-case???

[xjs3667]

ok so I'm think im guna do this on my xj, but wanted to try and get a little info first so I dont have to kick my self in the head trying to figure it out.

I have a np242 in there right now, and have an extra np 207 laying around.

I know a 207 will mate to a 207, and also 207 to a 231, and 231 to 231,

But I can't seem to find any info on a 207 to a 242, will these mate up? as in spline count, I havent took either one off to count the splines.

can anyone tell me what the spline count is input and output of each case??  heres what I got....

90' xj 4.0l AW-4 trans   np242

84' xj 2.5l A904 trans   np 207


Thanks