Engine Tuning Tips


Bob Gruitch just thought his car was not performing up to his expectations. A ’55 Chevy equipped with a 502 big block, square port heads and a Crane H296-2 camshaft should be more than enough power. But it lacked power and didn’t idle all that well, especially in gear. This shouldn’t be happening with an engine built by John Gianoli at Reggie Jackson’s High Performance Engine Shop, so Gruitch figured he had something wrong and brought the car to John Bishop’s Hot Rod Tuning Service to have it checked. He’s lucky that he did.


Holley carburetors have long been a staple in the go-fast world of high-performance motoring, whether it’s NASCAR, drag racing or on the street. Much like other performance-oriented products—perhaps even more so with a carburetor—a carburetor requires a fundamental setup and a degree of maintenance, and that’s considering you have chosen the correct-size carburetor for your application, at least to get it in the ballpark. Knowing how to adjust, maintain and even repair your Holley carburetor goes a long way toward helping to ensure that your carburetor will make optimum horsepower for a long time. Because of this, we decided to compile a few troubleshooting and repair tips for the popular 4150-series Holley carburetor, which is the series designation for Holley’s street/strip and racing carburetors.

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