#3XM. The G-Force Performance Racing Crossmember is a heavy duty, double hump transmission crossmember that was designed and fabricated exclusively for 1978 thru 1983 G-Body cars and is manufactured new from 2″ x 3″ (1/8″ wall) rectangular and 1/2″ plate steel. And best of all – IT BOLTS IN – no guessing, no cutting, no cussin’! This crossmember is built to take BIG BLOCK punishment and will also stiffen your frame to help straighten out launches. Another benefit of this crossmember is that installing a dual exhaust is a simple bolt-on operation that will provide clean, professional results. No floorpan modifications are necessary. (WILL NOT FIT POWERGLIDE OR MUNCIE 4 SPEED) This crossmember fits 1978 -1983 G-Body Cars with a Turbo 400 short tail or 200-4R Transmission. Comes with a Black Powder Coated finish. Note: 1978-83 vehicles with a 400 or 200-4R transmissions come with a frame extension.