Dana by Strange or Moser?

I'll see what Strange has to say, but can anyone give me some input regarding pinion angle? I had always planned on using my stock 8 3/4 in this car and most lately, decided on the Dana. I'll be using springs roughly equivalent to a Formual S spring with my Tremec. Should I be concerned about having them weld the perches on at any angle degree other than stock? An if stock, does anyone know what the angle is, just so I can verify with Strange that they know what that is? Really appreciate your input guys. I want to order this rear end this week if possible. Booooyah!