steering shaft spline count and size

[68on44s]

I am building a steering shaft for my 67 bodied 76 k5. does anyone know what size or imformation i need to find the splined parts to add to my recipe. I have many different size o ring sealed joints and the rest of the meterial, just not the splined female that goes to the box and the female spline for the column.... Im thinkin about trying to use the factory stuff, but it would be weak compared to what i could build with what im looking for. any imformation would be great