Four hundred twenty-seven is a number that carries a lot weight in the high-performance world. There’s Chevy’s fabulous 427ci big blocks, including the fearsome L88 (450 advertised horsepower, around 550 with open headers) and the fearsomer, all-aluminum ZL1 (430 advertised horsepower, close to 600 with open headers).
Ford’s 427ci FE engines were nothing to sneeze at either. You could get 500 horsepower out of one equipped with the NASCAR-spec high-riser heads. And let’s not forget the 427 Cammer—a 427 FE short block topped with single overhead-cam, hemi-style cylinder heads and capable of making 600-plus horsepower.
As awesome as these engines are, they have two disadvantages—physical size and weight. The all-aluminum ZL1 weighed around 550 pounds, about the same as an all-iron small block Chevy. But the iron block 427s weighed 680 pounds—a lot of weight to put over the nose of a Corvette or Camaro.
But thanks to modern technology, we can build a small block Chevy that displaces that magic 427 number. You get big cubic inches in a compact, lightweight package that fits under the hood of cars that could never accommodate a big block.
Even better, a small block 427 can make as much, if not more, power than the big blocks of old. To prove our point, we present three big-inch small blocks built by PowerNation TV’s Engine Power, Hot Rod, and Hemmings. They share similar components—a Summit Racing™ SPC engine block, a four-inch stroke crankshaft, a hydraulic roller camshaft, and 23-degree aluminum heads. The engines have different induction systems, and one has a slightly larger cylinder bore (4.165 inches vs. 4.125).
Each of these small blocks made peak horsepower around 6,000 RPM. Two made over 570 horsepower and one made over 600, all on pump gas. Torque ranged from 530 to 570 lbs.-ft.
Let’s take a look at these giant economy size small block Chevys. We’ve included links to the builds and major components so you can see what all went into them.
PowerNation TV Engine Power Super Street 427
Engine Power’s Pat Topolinski and Frankie Forman are no strangers to cubic inches or big horsepower. They combined both in their Super Street 427. The 10.26:1 compression, baby blue small block made 609 horsepower at 6,600 RPM and 530 lbs.-ft. of torque at 5,200 RPM. Nice parts matching, fellows.
Short Block
Summit Racing™ SPC Engine Block, 4.125-inch bores, 350 mains
Summit Racing™ Forged Pro Rotating Assembly, 4-inch crank, 6-inch connecting rods, pistons with 18cc dish
Summit Racing™ Pro SBC Stage 6 Hydraulic Roller Camshaft, 248°/256° duration @ .050, 0.550”/0.550” lift with 1.5 ratio rockers (.624” with 1.7 ratio rockers)
Cylinder Heads
Trick Flow Super 23 230 Cylinder Heads, 230cc CNC ported intake runners, 70cc CNC-profiled combustion chambers
Trick Flow PAC Racing Valve Springs, 1.550” dual, 427 lbs.-in. spring rate
Jesel Shaft-Mount Roller Rocker Arms, 1.7 ratio
Induction and Ignition
Edelbrock Super Victor 2 Intake Manifold
Edelbrock VRS-4150 Carburetor, 850 CFM
Wilson Manifolds Carburetor Spacer
FiTech Go-Spark Distributor
Hot Rod Magazine 427
Hot Rod’s 427 is very similar to Engine Power’s, proving great minds thing alike. Hot Rod used a slightly bigger Summit Racing Pro SBC camshaft and 1.6 ratio rockers instead of 1.7s. They also used a Flow R-Series intake manifold and a smaller 750 CFM Edelbrock VRS-4150 carburetor.
With this setup, the 10.25:1 compression engine made 559 horsepower and 531 lbs.-ft. of torque. Clearly the Edelbrock carb was too small, so Hot Rod made some pulls with 1,050 CFM Quick Fuel QFX and 950 CFM Quick Fuel Brawler carburetors. Their experiments were successful, pushing the 427 to 571 horsepower.
Short Block
Summit Racing™ SPC Engine Block, 4.125-inch bores, 400 mains
Summit Racing™ Forged Crankshaft, 4-inch stroke, 400 mains
Summit Racing™ Performance SBC Connecting Rods, 6″ long
Summit Racing™ Forged Pro Pistons
Summit Racing™ Pro GPX Gas-Ported Piston Rings
Summit Racing™ Pro SBC Stage 7 Hydraulic Roller Camshaft, 252°/258° duration @ .050, 0.550″/0.550″ lift with 1.5 ratio rockers (0.587″ with 1.6 ratio rockers)
Cylinder Heads
Trick Flow Super 23 230 Cylinder Heads, 230cc CNC ported intake runners, 70cc CNC-profiled combustion chambers
Trick Flow PAC Racing Valve Springs, 1.550″ dual, 427 lbs.-in. spring rate
Trick Flow Roller Rocker Arms, 1.6 ratio
Induction and Ignition
Trick Flow R-Series Intake Manifold
Edelbrock VRS-4150 Carburetor, 750 CFM
Summit Racing™ Aluminum Carburetor Spacer
MSD Pro Billet Distributor
Hemmings 70th Anniversary Small Block 435
Where Engine Power and Hot Rod zigged, Hemmings zagged. They increased their small block’s displacement to 435 cubic inches and compression to 12.5:1. They used Trick Flow DHC200 cylinder heads and topped a tunnel ram with a Holley Terminator X dual quad EFI system. Think of it as a 1970s-era street brawler that can actually idle.
Hemmings showed the 435 no mercy on the dyno. They made over 30 dyno pulls on pump gas and race fuel. The engine made 577 horsepower on pump gas and 584 horsepower on the good stuff. Torque ranged from 569 to 574 lbs.-ft. on both fuels.
And yes, Hemmings knows they could have made more power with a bigger cylinder head. But as it sits, the 435 is still one heck of small block.
Story Links
Episode 1
Episode 2
Episode 3
Episode 4
Short Block
Summit Racing SPC™ Engine Block, 4.125-inch bores, 350 mains
SCAT Forged Crankshaft, 4″ stroke, 350 mains
Summit Racing™ Pro SBC Connecting Rods, 6″ long
MAHLE Power Pak Piston and Ring Kit
Summit Racing™ Pro SBC Stage 7 Hydraulic Roller Camshaft, 252°/258° duration @ .050, 0.550″/0.550″ lift with 1.5 ratio rockers (0.587″ with 1.6 ratio rockers)
Cylinder Heads
Trick Flow DHC200 Cylinder Heads, 200cc CNC ported intake runners, 64cc CNC-profiled combustion chambers
Trick Flow Roller Rocker Arms, 1.6 ratio
Induction and Ignition
Edelbrock Street Tunnel Ram
Holley Terminator X 2×4 EFI System
Holley EFI Dual-Sync Distributor
MSD 6EFI Ignition Box
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