Our patent-pending tab-and-slot version of the TH400 Swap Block ® Transmission Mock Up Block provides accurate transmission mounting and yoke positions. This unique design is lightweight and comes disassembled for ease of shipping and storage. One tool accomplishes accurate placement of a TH400 transmission found in GM cars and trucks from 1964-1990. This mock up Transmission has a rear mount plate designed around the short tail TH400, but if a long tail is needed, you can bolt a tail shaft to the rearmost upright plate. Easily positioned by hand, there is no need to bench-press a heavy transmission into place for fitment and fabrication of Crossmember, etc. Save time and money and work more safely. Durable steel construction resists heat from welding, so unlike foam blocks, custom crossmembers can be fabricated close to the block.