uscartool and Mancini racing are the same part.
Here is the info off the cartool site:
Fits All A, B & E body cars
Small blocks, Big Blocks and Hemi
Automatics (727 & 904) and 4-speed
7260, 7290 and 1350 U-joints
5" ID loop for Stock or extra large diameter racing driveshaft
Stock Exhaust - Single and Dual - including headers
H Pipe Cars (Factory Hemi & 440-6 pack)
Most aftermarket large H & X pipe cars (TTi etc.)Now Available for A, B & E Bodies - Adjustable to fit all motor / transmission / exhaust combinations
67-72 A-Body now available