The 5.0L Fistfight began with a stock comparison between the H.O. 302 Ford and LB9 305 TPI Chevy. Part two introduced fuel-injected modifications including TFS aluminium heads, Comp cams, and EFI-specific intakes. Part three brought carburetion and nitrous oxide into the equation. The CNC-ported 170-cc 11R heads on the Ford allowed it to pull ahead in power production, but careful tuning in part three allowed the Chevy to close the gap once nitrous entered the mix.

For those noting the 11R head advantage on the Ford - the Chevy gets its answer here in part four. For this round, both engines receive a TorqStorm centrifugal supercharger with identical pulley ratios and blow-through carburetor configurations.

Dual-Plane Intake Preparation

In preparation for the supercharger, both 5.0L engines were configured with carburetion using dual-plane intakes rather than the single-plane setups from part three. On the Chevy, the Edelbrock Victor Jr. was replaced with a dual-plane Performer RPM Air Gap, paired with the same Holley 650 Ultra XP carb from the previous round. The result was notable: the 305 (and the 5.0L Ford) produced more power with the dual-plane intake than with the single-plane.

Equipped with the Performer RPM Air Gap, the 305 Chevy produced 381 hp at 6,100 rpm and 361 lb-ft of torque at 5,100 rpm.

The TorqStorm Supercharger

Boost for both engines came from TorqStorm. The centrifugal supercharger features billet aluminium construction, a proprietary ceramic bearing system, and coated internal components for temperature and wear control. The unit is rated to support over 700 hp on the right application - more than sufficient for either engine in this test.

The kit included the supercharger, mount, blower and crank pulleys with spacer, belt, tensioner, and a low-profile carb hat. Couplers, tubing, and a blow-off valve completed the connection to the carburetor. Installation required no oil feed to the blower and no drilling or tapping of the oil pan. Every fastener, hose, clamp, and belt needed was included. Total installation time was under one hour on the Chevy and less on the Ford.

Fuel Delivery Under Boost

To ensure adequate fuel delivery, the 650 Ultra XP was replaced with a dedicated blow-through carburetor from Carb Solutions Unlimited (CSU). The CSU carb has proven effective across a wide range of applications, from a supercharged 4.3L V6 to twin-turbo stroker big blocks. It was installed on the Performer RPM using a 1-inch Wilson spacer, which provided vacuum ports for the dyno readout and blow-off valve. The TorqStorm discharge tube included a provision to supply boost to the fuel pressure regulators, increasing fuel pressure in proportion to boost.

With the supplied 8-inch crank and 3.25-inch blower pulley, the TorqStorm supercharged 305 Chevy produced 559 hp at 6,000 rpm and 501 lb-ft of torque at 5,500 rpm.

The Ford's Turn

The Ford 302 received the same dual-plane treatment. The single-plane Funnel Web was replaced with a dual-plane Eliminator intake from Speedmaster. Still equipped with the XE274HR cam and TFS 11R cylinder heads from part three, the modified 5.0L Ford produced 422 hp at 6,400 rpm and 392 lb-ft of torque at 4,000 rpm in normally aspirated trim.

After installation of the identical TorqStorm supercharger, pulleys, and CSU carburetor, power output reached 619 hp at 6,200 rpm and 537 lb-ft of torque at 5,900 rpm. The CNC-ported 11R heads gave the Ford a 43 hp advantage in naturally aspirated form, which expanded to 65 hp under boost - consistent with the principle that boost acts as a multiplier of the original power output. This is why starting with a strong naturally aspirated combination before adding boost is always the recommended approach.

The Bigger Picture: Block Strength

The Ford produced the higher number, but the story does not end there. At this power level, the factory 5.0L Ford block enters a reliability concern. The lightweight, thin-wall casting that makes it initially appealing becomes a liability under excessive cylinder pressure. Late-model Ford 302 blocks have been known to split at similar power levels, particularly under the shock loads of a drag-race launch.

The small-bore Chevy 305, by contrast, offers improved block strength - enough to safely run at this power level and push further toward the TorqStorm's flow limit north of 700 hp. Add forged pistons with valve reliefs, a more aggressive cam profile, ported TFS heads, and potentially an intercooler, and the 305 can reach and exceed the Ford's 619 hp figure on a foundation built to sustain it.

The Ford won this round on the dyno. But for a combination that needs to survive repeated use, the Chevy block is the stronger foundation.

After running them stock, modified, and in carbureted trim with nitrous, it was time for the 5.0Ls to experience boost.

The 305 Chevy short block was in pristine condition at the start of modifications. Note the Fel Pro head gaskets installed with the TFS heads.

In part two, the Chevy received a Comp XR276HR cam - a hydraulic roller offering 224/230 degrees duration, 0.502/0.510-inch lift, and a 110-degree lobe separation angle.

The TFS Super 23 heads on the 305 offered a significant flow improvement over the stock iron heads, with 175-cc intake ports, a 1.94/1.50 valve package, and 56-cc combustion chambers.

The single-plane Victor Jr. was replaced by an Edelbrock Performer RPM Air Gap intake for this round of testing.

Feeding both the Air Gap intake on the 305 and the Eliminator on the Ford: a 650 Ultra XP carburetor from Holley.

In normally aspirated trim with the dual-plane Air Gap intake, the 305 Chevy produced 381 hp and 361 lb-ft of torque.

The TorqStorm kit included a crank pulley spacer designed to work with the factory crank pulley.

The lower crank pulley was bolted in place using the spacer and supplied mounting hardware.

Mounting brackets were bolted to the cylinder head, followed by installation of the TorqStorm centrifugal supercharger.

The tensioner system in the TorqStorm kit maintained consistent belt tension throughout all testing - a common problem area with supercharger installations.

The kit included a blow-off valve to manage pressure spikes during high-rpm, lift-throttle conditions. The vacuum/boost-operated valve also allowed excess blower flow to escape under light-throttle cruise.

A new addition from TorqStorm: a low-profile carb bonnet designed for applications with tight hood clearance.

Under boost with the TorqStorm supercharger, the 305 Chevy produced 559 hp and 501 lb-ft of torque.

The 5.0L Ford received an intake swap as well. The Funnel Web from part three was replaced by a polished Eliminator intake from Speedmaster.

Both engines ran under boost with a dedicated blow-through carburetor from Carb Solutions Unlimited.

Spark energy for both engines came from MSD distributors paired with a 6AL ignition amplifier.

In normally aspirated trim with the CNC-ported TFS 11R heads, the Ford produced 422 hp and 392 lb-ft of torque.

The TorqStorm kit for the Ford positioned the blower on the passenger side. Installation required bolting the mounting bracket to the cylinder head.

The blower and tensioner mount were secured to the cylinder head bracket.

The centrifugal supercharger was installed using the supplied Allen-head retaining bolts.

Both engines were tested with the same supercharger and 3.25-inch blower pulley.

Under boost, the supercharged Ford produced 619 hp and 537 lb-ft of torque - well within the splitting threshold of the thin-wall factory 5.0L block.

Carbureted 305 Chevy: Naturally Aspirated vs. TorqStorm Boost

After replacing the single-plane intake from part three, the 305 Chevy ran with a dual-plane Performer RPM Air Gap intake. In normally aspirated trim, the 5.0L Chevy produced 381 hp at 6,100 rpm and 361 lb-ft of torque at 5,100 rpm. With the TorqStorm supercharger installed, output reached 559 hp at 6,000 rpm and 501 lb-ft of torque at 5,500 rpm - a gain of 47% over the naturally aspirated configuration.

Carbureted 302 Ford: Naturally Aspirated vs. TorqStorm Boost

The 5.0L Ford received the same treatment, with a dual-plane Eliminator from Speedmaster replacing the Funnel Web. With the dual-plane and CNC-ported Trick Flow 11R heads, the 302 Ford produced 422 hp at 6,400 rpm and 392 lb-ft of torque at 4,000 rpm. With the TorqStorm supercharger, output reached 619 hp at 6,200 rpm and 537 lb-ft of torque at 5,900 rpm - a 46% gain, consistent with the percentage improvement on the Chevy.