Rocker shaft supports for FE motors

[chopper]

Jon Miller:

The problem with the stock shaft supports is that they do not adequately support the outboard rocker arms. If you look at RickLee's picture, the units have supports on the extreme ends of each shaft; the stock units do not have these supports. With the stock system, the outboard rocker arm is essentially rotating on a cantilever beam, resulting in the shaft outboard of the stand flexing during operation. This causes the valve geometry to change, especially under high rpm, resulting in the valve opening less than design. The aftermarket units use additional stands to support the outboard ends of the shaft and eliminate the flexing of the stock rocker shaft. This helps maintain the proper geometry for the outboard valves during operation.

I have a set of Dove rocker shafts and stands, holding a set of Harland Sharpe aluminum rocker arms. I had Dove rocker arms originally, but discovered that the Dove aluminum rocker arms for the FE engines do not have bushings installed. This results in the bare aluminum rocker arms riding on the steel shafts. My experience (which may be different from some others) was that the aluminum rocker arms failed after less than a thousand miles of relatively mild driving. At the first valve adjustment following installation (about 500 miles), all of the clearances were at least twice the original settings. At the second valve adjustment (1,000 miles), half of the rocker arms were worn well beyond any acceptable tolerance, and two had slop around the shaft hole exceeding an eight of an inch. When I called Dove, they told me that was their "standard design" for the FE engines and that lots of folks run the bare aluminum rocker arms with no problem. Short story, they refused to do anything about it. I threw away the Dove rocker arm garbage and installed the Harland Sharpe units, which have bronze bushings pressed into the arms. So far, 3000 miles later, no problems at all.

IMHO, as long as you don't exceed 5,000 rpm or so, you should have no problems. If you have a hot cam or rev above 5 grand, you may want to consider the aftermarket units.