DIY LS Trunion Upgrade With COMP Cams

By Brian Wagner October 28, 2019

The LS family of engines has become the most popular powerplant used for performance upgrades, and for good reason: they’re small, cheap, have loads of horsepower potential, are plentiful, and the aftermarket has showered the industry with go-fast parts for them.

If you’re looking to find one of these magical engines in a junkyard you might want to think about upgrading the stock rocker arm trunions before you try and make big horsepower.

The rocker arm trunion is part of the assembly that rotates the rocker arm each time the engine goes through the combustion process. When you upgrade the camshaft in an LS engine, the additional lift and duration will really increase the amount of stress on the stock rocker arm. The problem is that as stress intensifies it will cause the stock cap inside the rocker arm to move and eventually walk out of the rocker arm itself. When that cap moves too much the needle bearings that are inside the rocker arm will fall out and get circulated throughout the engine, causing a lot of problems.

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