Chevy L79 327 Engine I History, Specs, & Build Ideas
The GM small block Chevy is the most popular V8 engine ever produced, still more popular than the LS-series, as it has over 49 years of production and is still the king of performance parts. There are many versions of SBC engines, ranging from the smallest 262ci all the way up to the small block 400, though there are some aftermarket blocks that go far beyond 400 cubes. The hottest factory SBC of all time, however, is not a 400, 396, or even the standard-bearer 350, it is the 327 cubic inch SBC, specifically the L76 365hp that came in the 1964-’68 Corvette. The L76 was limited to the Corvette model, leaving other GM models desperate for a hot 327 V8. Enter the slightly less powerful brother, GM’s L79 engine was a powerhouse in its own right, and if you are looking for Chevy 327 build ideas, you have found the right place.
History of the L79 327 Engine and L79 Production Numbers
First installed into GM cars in 1965, the L79 engine was a powerhouse for the masses. This mouse motor boasted 350hp and 360 lb-ft of torque, though there is also a 325 hp version of the L79 as well. Unlike the L76 Corvette-only 327, the L79 327 was available in quite a few GM vehicles, including 1965-1968 Corvette, Chevelle, El Camino, Chevy II, and Malibu. Over 49,000 L79 327s were built during its four year run. L79-optioned Chevy II models are quite rare, only 6,791 units were sold with the 350hp 327 and only in 1966 and 1968, no 1965 models had the L79, and only six were built in 1967. The L79-powered Chevy IIs are considered one of the best factory muscle cars ever built.
What is the L79 327?
The 350hp L79 327 was the first 327 designed with a high-performance hydraulic camshaft. Up until then, all the GM high-performance small blocks used solid-lifter cams. The L79 327 is quite simply an L76 with a hydraulic cam. The specs are the same, they use the exact same heads, rotating assembly, and intake. There is a lot to be gained with the L79 as well, the hydraulic cam helps build more torque over the solid-cammed L76, but the L79 is a bit strangled with the factory-installed Holley 600-cfm carb. Going from a 600 to a 750-cfm carb can add more power, enough to eclipse the 365hp L76.
L79 Engine Identification/Codes
Identifying an L79 is a little difficult, as GM used the same blocks for various versions of the same size engine. The 327 engine has a pad on the front passenger side cylinder head. The code lists the assembly plant, date of build, and a suffix code, which is the one you are after. The first letters should be F (Flint), S (St. Catherines), K (Ontario), or T (Tonawanda). The next numbers are the build date in month/day/year. The suffix for the L79 327 varies by year and model, making it difficult. The suffixes note the type of induction, transmission, and whether or not the engine has AC. These suffixes may vary slightly as GM did change things erratically at times.
Suffixes for 327 L79
Corvette: HT, HD, HP, HV, HU, KH
Chevelle: EC, ED, ER, ES, EP
Chevy II: ZG, ZH, ZI, ZJ, EP, ML
L79 Chevelle and L79 Chevy II engines in 1965-’66 had “Turbo-Fire 327” valve covers, which differ from the standard 283/327 covers. For ’67-’68, L79 Chevelles and L79 Nova 327 engines had plain chrome valve covers. All L79 Corvette engines have the standard cast aluminum “Corvette” script valve covers.
Block casting numbers for the L79 are a little sketchy as well, here is the accepted casting number list for 350 hp L79 327 engine blocks:
1965: 3782870
1966: 358174, 3858180
1967: 3892657
1968: 3914678
The cylinder heads have a casting number between the first and second cylinders.
Cylinder head IDs
1965: 3782461
1966: 3782461, 3890462
1967: 3890462, 3917291 (325hp rating)
1968: 3917291, 3917292
327 L79 Engine Specs:
Horsepower: 350hp @ 5,400 rpm
Torque: 360 lb.-ft @ 4,000 rpm
Compression Ratio: 11:1
Displacement: 327 cubic inches
Cylinder Bore: 4.001”
Stroke: 3.25”
Heads: Iron “double-hump” 461 castings, 2.02” intake, 1.60” exhaust valves
Crank: Forged steel
Intake: aluminum dual-plane high-rise four-barrel
Induction: 600-cfm Holley four-barrel
327 L79 Cam Specs this should be a sub-L79 vs L76 Engine
Lift: .447” int/exh
Duration @.050”: 221 int/exh
LSA: 114
327 Build Ideas
You don’t have to start off with an original L79 327 block, in fact an original L79 327 is quite valuable and hard to find. One recently sold as a bare block for over $1,000. Chevrolet 327s were only made from 1962 through 1969, and the rare option units like the L79 are hard to find. The L76, the most powerful carbureted 327, sold in higher numbers than the L79. GM did however use the same casting for most of the 327s, so recreating an L79 is not too hard. You can even build a large-cube version of the L79 by using a 350ci block with 461 heads.
Best Heads For 327 L79
The original heads used on the L79 are the same as the L76 and L84, the famed “Camel Hump” 461 castings with 2.02”/1.60” valves. Keep in mind that most 461 double-hump heads have 1.94”/1.50” valves, only the select few used on L79, L76, and L84 engines had the larger valves. These heads can be found at swap meets and online resellers, but there is another option, one that brings some modern technology to the 327: Speedway Motors' aluminum 461 heads. Designed to match the original design that came out on the 1961 Corvette Fuelie, while shaving 40 pounds of unnecessary weight, they feature 180cc intake and 62cc exhaust ports, same as the original 461s. These flow an impressive 232 cfm at .500” lift on the intake, and 173 cfm at .500” lift on the exhaust side. To further the “L79 Corvette engine” look, the aluminum 461 heads have raised valve cover rails, so you can use roller rockers with the factory Corvette-logo valve covers.
Building an L79 Chevelle clone requires the right valve covers as well. All Corvette engines at the time used the same finned aluminum covers, but Chevelle/Malibu (production numbers include Malibu models), El Camino, and Chevy II (commonly referred to as an L79 Nova), had different valve covers. A simple set of plain chrome covers with this “327 Turbo-Fire 350 Horsepower” decal will complete a ’65-’66 Chevelle, El Camino, or Chevy II L79 build.
More 327 Build Parts from Speedway Motors
L79 vs L76 Engine
Like the L76/L84 327s, the L79 has 11:1 compression, which requires 93 octane fuel. Because there is no EFI system controlling the spark timing, you can’t get away with lower octane without detonation, and nobody wants to beat up the pistons. Luckily, the L79 has a hydraulic camshaft, so you don’t have to adjust the valve lash all the time. The only real difference between the L79 and the L76 is the camshaft, where the L76 has a solid lifter cam, the L79 was the first high-performance hydraulic lifter cam that GM made.
Another key component is an L79 intake manifold, which is an aluminum dual-plane hi-rise unit. Speedway Motors offers a new casting to satisfy your L79 induction needs for any L79 build (or L76/84). While the correct carburetor is a 600-cfm Carter four-barrel, the L79 has been dyno tested to make over 380 lb.-ft of torque with a 750 Holley. Nearly 400 lb.-ft of torque from a 327 with just a carb change seems crazy, especially considering the hydraulic cam, but the dyno doesn’t lie. Using the original GM specs, Comp Cams offers an L79 Nostalgia Plus camshaft, that very closely matches the original specs. The Comp unit has a hair less lift at .468”, and slightly more duration at 229 in/236 exh. The reason for the minor changes is to give you the same experience of the original sound and feel, while taking advantage of modern lobe design for better throttle response, it is the best of both worlds.
The Chevrolet L79 327 engine may not be the single best 327 ever built, but it is really close and in reality, it is more drivable on a daily basis than the L76, because of the hydraulic cam. Besides, with a few tweaks, an L79 clone can quickly catch and surpass the L76’s 365hp rating. If you have a hankerin’ for some Mighty Mouse hot roddin’, then the L79 327 is the one to aim for. For more information on the 1965 Corvette, visit the GM Heritage Center.