18 When installing non-stock heads, unless they’re the same height as factory, you will need longer pushrods, as TFS notes in its instructions. Our buddies at Comp Cams sent us their adjustable pushrod kit (comes with three different-length checking pushrods) so we could figure out the length necessary. Once calculated, we ordered up a set of Comp 7757 9.600-inch-length, one-piece, 3/8-diameter, heavy-wall pushrods. Since pushrod length can vary by application and block (deck height, whether a head’s been milled, etc.) it’s always best to measure pushrod length to verify you’ve got the right ones. Pushrods too long or too short can wreak havoc in the valvetrain and lead to serious engine damage like valves hitting pistons.