Transmission CrossmemberTH4001978-88 Malibu/Regal/Cutlass/Monte Carlo/Grand Prix/GNDoes not fit Cutlass Supreme or El Camino Models Installation Notes:If installing on a 1978-1983 G-Body you will need part number 555-54718 frame extension. This piece is designed to replicate the longer driver side frame rail of the 1984 and later GM G-Body cars giving you the proper mounting locations for this crossmember.Some 1983 Hurst Oldsmobiles were originally equipped with a 2004R transmission and will not require this frame extension. If you are unsure, 1984 and later models will feature two mounting locations for the transmission crossmember approximately 14 in. behind the front set of mounting holes.Crossmember is designed for 1978-1988 G-Bodys that were originally equipped with an SB-Chevy. Does not fit Cutlass Supreme models or El Camino. Engine and transmission swaps may require some additional modifications & fitment of components. Hardware is not included.