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Speed Secrets: Building and Testing a L79 Small Block Chevy

The specs of the muscle car era engine were pretty standard across the board, but GMs L79 had a legendary reputation. To take a look at what set the L79 apart from the rest, Speed Secrets’ Richard Holdener teamed with Comp Cams to build a reproduction L79. With 4 bolt mains, a forged crankshaft, and 11:1 compression pistons, the main thing that was different in the L79 was the hydraulic Flat Tappet Camshaft. Despite being Chevys biggest over the counter seller in the muscle car era, the L79 camshaft was discontinued, but luckily Comp Cams offers a reproduction of the legendary 327s camshaft along with most of the other valve train components. 

Starting with an 11:1 4 bolt short block, Richard adds on Comps 12-106-3 Cam that features a  .447 lift, 222 duration, and a 114 LSA. Sticking with the original theme of the engine, 2.02/1.06 valved Fuelie heads are used along with Comp rocker studs, guide plates, and stamped steel rocker arms. Topped with an aluminum high rise intake and a 750 CFM Holley carburetor, the 350 factory horsepower rated L79 engine made 346 HP @ 5,400 RPM and 383 lbs/ft of torque @ 3,900 RPM. 

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While these numbers are impressive and in line with the factory HP rating, it is most likely more power than any factory L79 engine put out. Considering that originally the L79 engine was equipped with cast iron exhaust manifolds and at most a 650 CFM carburetor and this Dyno testing was conducted with the use of long tube headers and a 750 CFM carb, GM’s factory power rating had to be a little off. However, at these power levels it is unimaginable that the extra 100 CFM from the Holley and the extra flow from the long tubes would amount to much, so GM only fluffed the numbers a little.

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