These 1.7:1 roller rockers will allow your Jeep, instead of falling on it’s face at 3800-4200rpm, to carry that out to 4600-4700rpm (right where the automatic transmission shifts at). This is a great option to squeeze more out of your stock cam, even without a supercharger.
Adjustable type rocker arm can be adjusted to compensate for engine rebuilding, (milling the heads, decking the block, etc.), large increases in lift, and for solid cam’s that require a certain amount of lash. An adjustable rocker can handle any cam type or size as long as the correct components & geometry are used.
These rocker arms have been specifically designed in conjunction with Harland Sharp to provide the correct geometry for the AMC/Jeep inline six cylinder engine family, including the 232, 258, and 4.0L. They provide an actual 1.7:1 ratio (over the stock 1.6:1), in addition to eliminating the loss of lift resulting from flex of the stock weak rocker arms. They will fit the ’91 and newer 4.0L head, but may require additional spacers to clear the valve cover.
What you get:
- True 1.7:1 (if you have a more aggressive cam than stock, you should consider the 1.65:1)
- Additional 2-3 degrees of duration
- Additional 0.025″ lift