Making it possible to fit almost any GM transmission into your G-Body alongside an LS or LT, this updated transmission crossmember should be used with an aftermarket urethane transmission mount such as the Hooker Blackheart 71223029HKR or 71223030HKR or equivalent. Due to the unique design geometry of this transmission crossmember, attempts to install it with headers and/or engine mounting plates/brackets other than those developed by HOOKER™ for this application will more than likely not be successful. When used with the related Hooker™ 12643HKR or BHS5179 engine mounting bracket kit, this CAD designed transmission crossmember will replicate the stock small block Chevy engine/transmission inclination angle and eliminate or minimize the need to adjust the rear pinion angle in stock to moderately lowered chassis applications. Depending on the transmission, the following part numbers will be necessary: *No additional adapter needed for TH400/200R4/T-56/Magnum. TH350 Transmissions can reuse the factory transmission crossmember, but the slots in the center of the crossmember will need to be elongated in the forward direction. 12655HKR - 4L60/65/70/75 Transmission Adapter 12656HKR - 4L80/85 Transmission Adapter BHS5181 - 10L80/10L90 Car Transmission Adapter - must be used with BHS5182 (for G-Body) BHS5182 - 6L80/90, 8L45/80/90, 10L80/90 Transmission Adapter BHS5183 - Tremec TKX 5-Speed Transmission Adapter