Do you need stock length, or longer? Frankly, I would ALWAYS put in longer studs. The new style taper seat aluminum wheels have to have longer than stock. (610-446 are longer rears, don't know the fronts. Drum studs are different than discs).
And to the best of my knowledge, the left hand thread studs are not available new anywhere, except certain Mopar vendors.
Edit: I have 3" moroso studs in my front drums, but I have no idea what the part number is, they've been there for 40 years.