For G-Body, use with 12644HKR-1 Trans Crossmember (no additional adapter needed for TH400/200R4/T-56/Magnum) For 2nd Gen F-Body, use with 12616HKR-1 and Hooker 12613HKR or 12512HKR engine mounts Also recommended: standard GM Transmission Mount (ex: 71223029HKR, 71223030HKR, or 24350) Other Available Adapters: 12655HKR - 4L60/65/70/75 Transmission Adapter - use with 12644HKR-1 12656HKR - 4L80/85 Transmission Adapter - use with 12644HKR-1 BHS5181 - 10L80/10L90 Car Transmission Adapter - must be used with both BHS5182 and 12644HKR-1 BHS5182 - 6L80/90, 8L45/80/90, 10L80/90 Transmission Adapter - use with 12644HKR-1 BHS5183 - Tremec TKX 5-Speed Transmission Adapter - use with 12644HKR-1