What's the difference between a Corvette and a billet servo? I have seen them both referred to but dunno what the difference is?

 

The after market billet servo makes 2nd gear even firmer than the Corvette servo. I see no need for this piece. I have several 700R4's in the 10's & 11's with the Corvette servo and have not found that the bigger servo was needed in any application as of yet. If you work with the accumulation, you can make the shift as soft or as hard as you want with the Corvette servo.