I don't know what size shafts they run in NASCAR, but you may be able to come across some blank lockers or side gears in nascar country.Thanks tbi. 40 spline was definetly on my list to call, they seem to always be willing to help or our community as well as provide input here on the board. Mark Williams was another I've learned of in the 9" research.
Also found a couple experienced edm shops near Charlotte, with Nascar history. Plan to talk to them as well.
Or at least get a 31 spline locker side gears cut out to 14b 30 spline.