The universal transmission cross member is constructed of 1-1/2'' x .134'' Mild Steel Tubing.

The 1978-88 G-Body crossmember is made from 1-1/2'' x 2-1/2'' x .120'' Rectangular Tubing. Double hump design is made to be used with dual exhaust kit 555-30556 and headers 289-85121 (black painted) or 289-86121 (cerama-coat). Hardware not included.