Build Your Own High-Compression Small Block Chevy with Engine Power Compression Obsession 406 CID Chevy Parts Combos

PowerNation TV’s Engine Power team built a 360 cubic inch small block Chevy to use as dyno mule. They used the engine to test the effects of compression ratio on fuel octane requirements and horsepower. Watch these Engine Power episodes on PowerNation’s YouTube channel and see what they found out—the results might just surprise you:

Compression Obsession Parts 1 and 2
Compression Obsession Part 3

Then disaster struck. The little 360 was sitting in Engine Power’s dyno room when the facility lost power during a bitter cold snap. Since the dyno room is hooked to outside air, it got cold enough to freeze the coolant in the engine block. As the coolant expanded, it literally cracked the sides of the block, turning it into junk.

That didn’t stop Engine Power for very long. They built a 12.4:1 compression, 406 cubic inch small block Chevy by combining the good parts from the broken 360 with a bottom end based on a block from a 400 cubic inch small Chevy. The 406 made 618 horsepower and 559 lbs.-ft. of torque on E85. Running 104 octane race gas, it made 642 horsepower and 568 lbs.-ft. of torque. That’s quite a dyno mule.

Check out the 406 build and dyno sessions on PowerNation’s YouTube channel and the parts used in our Engine Power Compression Obsession 406 CID Chevy Parts Combos.

Short Block
The 400 block came from the factory with four-bolt mains, making it a rare beastie. Engine Power bored it .030-inch over to accept new Mahle forged pistons. The block was fitted with King XP-Series rod and main bearings, Clevite cam bearings; and ARP High Performance Series main cap bolts.

The Mahle PowerPak pistons have a 4.1cc dome and two valve reliefs, and come with a low-drag ring pack, wristpins, and spiral locks. The rest of the reciprocating assembly included the crankshaft from the 400 with journals turned .010-inch under and a set of Scat Pro Stock 4340 steel connecting rods from the broken 360. The I-beam rods feature a one-rib cap design and ARP cap screws to handle the stress of big horsepower and high compression. Scat even goes to the trouble of weight matching the set to make balancing easier.

Since 400 small blocks are externally balanced, the reciprocating assembly was balanced with a Summit Racing™ Bracket Racer SFI Harmonic Damper and Summit Racing™ Billet Steel Flywheel. The steel damper has an injection-molded and bonded elastomer, is spin-tested to 12,500 RPM, and meets SFI-18.1 standards. The flywheel is SFI 1.1-approved and drilled for both Borg & Beck and Long-style clutch assemblies.

Engine Power reused the custom-ground COMP Cams solid roller camshaft from the 360. It is rated at 252°/260° duration @.050-inch and .653"/.660" lift with a 110-degree lobe separation angle. They also reused the Trick Flow® Billet Steel timing set from the 360, which we include in the combo. The timing set comes with billet steel gears and a double roller timing chain. The crank gear has a nine-position keyway that allows you to fine-tune cam timing.

Rounding out the combo is a Fel-Pro rear main seal, Melling brass freeze plugs, and a Dura-Bond block hardware kit. The Dura-Bond kit includes woodruff crank keys and dowels for the cylinder heads, transmission, timing cover, and oil pump.

Top End
The valvetrain assembly from the 360 was transferred over to the 406. It’s based on AFR 220cc SBC Eliminator cylinder heads. The heads feature CNC-machined 220cc intake and 80cc exhaust runners, CNC-machined 65cc combustion chambers with 2.110-inch/1.600-inch valves, and 1.550-inch PAC Racing valve springs rated to .710-inch valve lift. The Eliminator heads flow 326 CFM of air at .700-inch valve lift.

The heads were fitted to the block with Cometic MLS head gaskets and ARP High Performance Series cylinder head bolts. The gaskets have a .027-inch compressed thickness. Combined with the 65cc combustion chamber in the AFR heads and the Mahle piston’s 4.1cc domes, the engine’s measured static compression ratio is 12.42:1.

COMP Cams Endur-X roller lifters and Hi-Tech pushrods transfer cam motion to 1.5 ratio Jesel Sportsman Series shaft roller rocker arms. Designed specifically for AFR 210cc and 220cc Eliminator heads, the aluminum rockers can handle open valve spring pressures of up to 900 pounds while maintaining precise valve lash settings. They even fit under a standard-height valve cover.

The Edelbrock Super Victor intake manifold and a two-inch tall Wilson four-hole tapered aluminum carburetor spacer also came from the 360. The Super Victor has extended runners that deliver more torque from 3,500 up to 8,500 RPM. That means excellent throttle response, off the corners in oval track racing and improved 60-foot times in drag racing.

The Wilson carb spacer has a variable-radius taper design that maximizes airflow through the carburetor and enhances air/fuel distribution for more horsepower. The extra height also allows air and fuel a straighter shot into the cylinder head intake runners.

Engine Power used two Quick Fuel carburetors during dyno testing—an 850 CFM Q-Series for E85 and a 950 CFM Black Diamond Series for gasoline. Our combo includes the Black Diamond Series carburetor. It has mechanical secondaries, a Proform high-flow main body, and CNC-machined billet aluminum metering blocks with four-stage emulsion to provide more precise fuel metering, improved throttle response, and a more uniform fuel performance curve.

Completer Parts
Engine Power reused the high-volume oil pump from the old 360 engine and the oil pan from the 400. Our combo includes a high-volume Summit Racing°™ Oil Pump and Pickup Kit, an ATP stock replacement oil pan, and a Fel-Pro reusable pan gasket. Since the 400 uses a block-mounted oil dipstick, we included a Lokar Midnight Series oil dipstick.

Since they were testing with E85 and 104 octane race gas, Engine Power needed rock-solid ignition timing. They used an MSD Flying Magnetic Crank Trigger and Pro-Billet Crank Trigger distributor. The crank trigger’s "flying magnet" design produces accurate timing signals without the false triggering issues that can lead to poor performance or even engine damage.

The Pro-Billet distributor has a CNC machined billet aluminum housing, a large HEI-style cap with widely spaced terminals to prevent arcing inside the cap, and an oversized polished steel shaft with a friction-reducing coating. The distributor must be used with an MSD 6-, 7-, or 8-Series ignition box.

Engine Power made a set of custom-fit ignition wires using a universal-fit MSD 8.5mm Super Conductor wire set. They send spark to a set of NGK Racing spark plugs.

Rounding out the combo are a pair of Summit Racing™ Die-Cast Logo Aluminum Valve Covers, a Summit Racing™ Timing Cover, and an Allstar Performance fuel pump blockoff plate. The valve covers have a Chevrolet bowtie logo and a black powdercoat finish.

CHECK OUT THE ENGINE POWER COMPRESSION OBSESSION 406 CHEVY PARTS LIST