Our LT4 Conversion
The LT4 was a one-year-only version of the LT1 that came in '96 Corvettes with the six-speed transmission. Some of these engines also found their way into the engine compartments of special-edition '97 F-cars. The LT4 made just 30 more horsepower than the standard LT1, but the power under the curve was better.
For several years, GM was selling a conversion kit to convert a stock LT1 to LT4 specifications, but it has been discontinued. Some of the parts are available separately, however.
Our LT4 conversion consists of Edelbrock's RPM XTreme cylinder heads, an LT4 intake manifold, Harland Sharp 1.6:1 rocker arms, and a Comp Cams camshaft with specs very similar to GM's famous Hot cam. The heads are called partial CNC'd, meaning the combustion chambers are fully CNC-machined, but the runners are not. Edelbrock says the difference in airflow is minimal compared with a fully CNC'd runner, but the difference in price is substantial.
Note that the LT4 cylinder heads have raised runners, and therefore you must use an LT4 intake manifold and intake gaskets. The standard LT1 stuff will not fit.