Quick transmission question

[Furious 64]

What's the difference between a 18 spline and a 23 spline 4 speed transmission? I'm restoring a 1964 sport fury with a 440 in it and I was wondering what the differences in performance are, if there is any and what you guys would recommend. Just need some general information about them.
Thanks,
Tyler

 

[RustyRatRod]

5 splines and a bigger input shaft diameter for the 18 spline.

 

[benno440]

18 spline is the stronger box theres lots of infor on google or brewers performance.com

 

[Meep-Meep]

The 18 spline box has the obvious differences and also has a coarser pitch on the gear teeth. The individual gears are bronze bushed where they ride on the main shaft and the later (68 up) use the larger 308 bearings. There is also a miniscule difference in first gear ratio. 2.65:1 on the 18 spline and 2.66:1 for the 23 spline.

 

[Furious 64]

I live close to Brewer's. I'm going to have to go and talk to them in person!