I'm going to assume your discussing the axles from a 8 3/4 or is it a Dana 60 with the 30 spline axles? Either way all the current after market axles for the 8 3/4 and Dana 60 with the 30 spline axles use either 30 degree or 45 degree, I'm not sure which is correct
Originally Mark Williams used the other non stock angles on his axles and spools but discontinued doing that a long time ago due to customer input according to one of the techs. when I ask him about on their current spline angles several years ago
Copied from Mark Williams Web page
"1.
Are all axles with similar spline counts interchangeable? No! For example, an OEM 35-spline Dana axle and a special MW 35 spline axle are not interchangeable because the MW spline features a 45-degree pressure angle, which differs from stock Dana 30-degree configuration. Mark Williams does, however, offer Hi-Torque forged steel axles with OEM type splines. Please read additional spline text on page 3"
"
Spools A spool is single piece carrier and does not offer any compensation for different rotating speeds in the wheels. Because of additional stresses created by a spool, it is not a good idea to run stock-spline axles with a spool. Spools should be run in race only type applications and are not intended for use on the street."
"
4. Involute Splines All OEM axle differentials have involute splines; their face is slightly curved to provide optimum contact and even pressure distribution during acceleration. Some aftermarket axles are made with straight-cut splines. They are not a correct engineering design and result in sloppy fitting practices. This creates high stress points, which can result in premature spline failure. Only involute spline profiles should be used to assure uniform loading and proper mating properties with spools and OEM components..."
