If youre looking for the power of headers, a distinctive look and the dependability of cast iron, we have the hot setup for small-block Fits Chevys: the Tru-Ram exhaust manifold. We started with a clean slate and designed an exhaust manifold that will give you looks and performance never before available in cast iron. provides a tight-fit for steering and clearance issues. Flows better than original Corvette manifolds. Same performance as tube headers with classic ram horn styling. Offers a distinctive look. 2-1/2" collector uses standard reducers or tight tube extensions. Includes mounting hardware and gaskets. Note: The exhaust port size is square and large enough for most round port heads. It measures 1.375" x 1.375" and should be sufficient for most small block cylinder heads. Variation in location of spark plugs on aftermarket heads makes it impossible to verify that the Tru-Ram will fit all heads on the market, but it will clear most straight and angle plug heads. 3-1/2 " from cylinder head surface to outside point. 3-1/2 " from bolt center to top of manifold. 5-1/2 " from manifold bolt center to bottom of collector. 2-1/2 " collector uses standard header reducers. 3-1/2 " from cylinder head surface to outside point. 3-1/2 " from bolt center to top of manifold. 5-1/2 " from manifold bolt center to bottom of collector. 2-1/2 " collector uses standard header reducers.