Because its a trap door road race pan. I agree they're big $$$ but they are super nice and I plan to hit some hi-G loads. It uses the same pickup as the 31000.
FYI - I do not believe the pickup is the same part number. I called milodon twice about it. Both guys said it was a different part number. The first guy gave me the part number and it was the same as the 31000 pickup. When I called the second time, the guy said their catalog has a mis-print for which pickup is needed for the RR pan, and that the RR pan pickup is slightly more vertical into the pan because of the baffling.
All that to say, call Milodon to verify which pickup is needed before you buy.
