PROJECT GROUNDHOG PART 2

We finish assembling our rescued 5.3L LS engine

- JEFF SMITH

When we left Project Groundhog at the end of Part 1, we had just finished assembling the short-block. To briefly sum up the scope of the build, we started with a down-in-the-dirt (literally) Gen III 5.3-liter truck engine that we bored out roughly 0.110-inch, to 5.7-liter specs. The approach was to build this engine correctly with no shortcuts, but also to try to maintain a reasonable budget.

Our goal was a mild street engine that would make around 425-430 horsepower using a Summit Racing camshaft, their muscle car oil pan, and a carbureted intake manifold so we could stuff it into something like a Chevelle or possibly a 1948-1953 Chevy pickup. The additional performance parts bumped the price, but they were necessary to arrive at our goal.

ASSEMBLING THE LONG-BLOCK

With the most challenging part of the shortblock assembled, we could now deal with the heads, valvetrain, and intake portion of the engine. We elected to retain the stock 5.3-liter cathedral-port heads that were in decent shape. The stock heads come with 1.89- and 1.55-inch valves, and our machinist, Mike Mathis, of Williams Machine Shop in our new southern lowa location, performed all our machine work.

Despite their rough appearance, the stock cylinder heads required only one valveguide to be replaced, as the others were in good shape. We elected to use new valves to improve overall performance, and Mathis completed the work with a simple three-angle valve job. He also milled just enough off the heads to ensure a flat sealing surface.