correct brake bleeder screw

[dumpy johnny]

i'm going through my 72 c30 1 ton dump which i started 2 years ago. its got a rebuilt 350 , 465 trans w/ gear vendors overdrive. new dump pump, vintage air. I got rid of all the rust,which there was plenty of. anyway im close to done but while bleeding the brakes, 1 of the front bleeder screws stripped, i got it out but having a hard time finding a replacement. been to Nappa, Auto Zone, Advanced, and local auto parts stores. the thread is 3/8x24 but all the screws i've gotten don't hold the fluid. On the stripped one i have, the distance from the treads to the end of the screw is longer than the ones given me at auto parts stores. Does anyone know where or who makes the screws that will work?Thanks, Johnny