I looked at this for a GM 55T axle & found the same.. Randys has a 3.38 ratio for, are you ready, $552.13..
I am keeping the 3.90 & going with a 700R4 tranny.. this will give me 2230 RPM @ 70 MPH...
About the same money, but I would rather spend it on the tranny...
Good luck,
TC