Okay Car Crafters, stuff just got real. Our 5.0L Fistfight began innocently enough, with a comparison between the stock H.O. 302 Ford and LB9 305 TPI Chevy. Part two brought an array of fuel-injected mods, including TFS aluminum heads, Comp cams, and EFI-specific intakes. We rounded things out in part 3 with the perfect combination of carburetion and nitrous oxide. The use of CNC-ported, 170-cc 11R heads on the Ford allowed it to surge ahead in power production (with no similar heads available for the small-bore 305), but careful tuning in part three allowed the Chevy to make up ground once we added nitrous to the mix. For Chevy fans still complaining about the 11R head swap on the Ford, rest assured the Chevy will exact revenge here in part 4, but you’ll have to wait until the end to find out how. For part four, we decided to introduce boost to the equation by adding a TorqStorm centrifugal supercharger to the mix. In keeping with the spirit of the competition, both the Ford and Chevy received the same supercharger, pulley ratios and blow-through carburetor. How did they do? Let’s find out!

In preparation for the supercharger, we elected to configure the 5.0L duo once again with carburetion, but instead of the single plane intakes, we opted to install dual-plane intakes. For those questioning our use of dual planes on a blow-though application, put your fears to rest- it not only worked, it worked well. For the Chevy, this meant removal of the Edelbrock Victor Jr. intake and installation of a dual-plane, Performer RPM Air Gap. The Air Gap was combined with the same Holley 650 Ultra XP carb run in part three, but an interesting thing happened, the 305 (and 5.0L Ford) made more power with the dual plane intake. 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. Satisfied we had made the right intake choice, it was time for some boost.

Boost for the Ford and Chevy came from the boys over at TorqStorm. The centrifugal supercharger offered a number of desirable features, including billet aluminum construction, a proprietary ceramic bearing system, and coating of internal components for temperature and wear control. Perhaps the most important part of the equation was that the supplied supercharger was capable of supporting over 700 hp on the right application, easily more than we had planned for either of our engines. The kit included the supercharger, mount, blower and crank pulleys (and spacer), along with the belt, tensioner, and new low-profile carb hat. Also included were couplers, tubing and a blow-off valve to connect the supercharger to the carb hat. Installation was beyond simple, with no need to supply oil to the blower or drill and tap the oil pan to serve as an oil return. Every nut and bolt, hose, clamp and belt needed for the installation was supplied in the kit. Bolting on the supercharger took less than 1 hour from start to finish, even less on the Ford (we already had practice).

To ensure adequate fuel delivery under boost, we swapped out the 650 Ultra XP for one modified by the blow-through experts at Carb Solutions Unlimited (CSU). The CSU carb featured a variety of modifications designed to optimize performance on a blow-through application. Having used this carb countless times in the past, we can say it was both effective and versatile, allowing us to dial in the air/fuel mixture on anything from a supercharged 4.3L V6 to a twin-turbo, stroker big block. The CSU carb was installed on the awaiting Performer RPM using a 1-inch Wilson spacer. The spacer provided the necessary vacuum ports for the dyno readout and blow-off valve. The discharge tube supplied by Torqstorm featured a provision to supply boost to the fuel pressure regulators, which increased fuel pressure (to the carb) in proportion to boost. Equipped 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 302 was given the same dual-plane intake treatment as the 305. On the Ford, we replaced the single-plane Funnel Web with a dual-plane Eliminator intake from Speedmaster. Fresh from testing in part three with the nitrous, the high-mileage 302 Ford was still sporting the XE274HR cam and TFS 11R cylinder heads. Equipped with the dual-plane Eliminator intake, the modified 5.0L Ford produced 422 hp at 6,400 rpm and 392 lb-ft of torque at 4,000 rpm. After installation of the very same TorqStorm supercharger, pulleys and CSU carburetor, the power output jumped to 619 hp at 6,200 rpm and 537 lb-ft of torque at 5,900 rpm. Thanks to the CNC-ported, 11R cylinder heads, the Ford started out 43 hp stronger than the Chevy. This increased to 65 hp under boost, which isn’t unusual as boost is often times a multiplier of the original power output. This multiplier effect is why we always recommend starting with a powerful normally aspirated combination before adding boost.

While it might seem the Ford came out on top-thanks to us cheating up the 5.0L with ported heads, that isn’t the whole story. The 305 Chevy might be at a disadvantage due to the smaller bore size and attending availability of cylinder heads, but we have now reached a limitation specific to the 5.0L Ford. It is at this power level that the strength of Ford block comes into question. The lightweight, thin-wall casting might make the Ford block initially appealing, but care must be taken when subjecting it to excessive cylinder pressure. We’ve seen late-model Ford 302 blocks split with even less power, especially when subjected to the shock loads of a drag-race launch. By contrast, the small-bore, Chevy 305 should offer improved strength over the Ford, allowing owners to not only safely run this current power level, but take the combination even further, closer to the flow limit of the TorqStorm supercharger (north of 700 hp). Add some forged pistons with valve reliefs, slightly wilder cam timing and ported TFS heads and the Chevy boys will putting some hurt on the 5.0L Ford. Add boost, and possibly an intercooler, and you can not only reach, but easily exceed 619 hp produced by the blue-oval boys. The Ford may have won this battle, but we’d pick the strength of the Chevy block if we actually had to go to war.

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

The 305 Chevy short block was in pristine condition when we started with our modifications. Note use of the Fel Pro head gaskets once we installed the TFS heads.

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

The TFS Super 23 heads used on the 305 offered a dramatic increase in flow over the stock iron heads (from any 305). Credit the 175-cc intake ports, a 1.94/1.50 valve package and 56-cc combustion chambers.

For this test, the single-plane, Victor Jr. was replaced by an Edelbrock Performer RPM Air Gap intake.

Feeding the Air Gap intake on the 305, and Eliminator on the Ford, was this 650 Ultra XP carburetor from Holley.

Run 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 this crank pulley spacer designed to be run in conjunction with the factory crank pulley.

Using the spacer and supplied mounting hardware, we bolted the lower crank pulley in place.

10_Next, we bolted the mounting brackets to the cylinder head and installed the TorqStorm centrifugal supercharger.

We liked the tensioner supplied with the kit. Belt tension is often a problem with superchargers, but the system on the TorqStorm kit worked well in all of our testing.

The kit also included this blow-off valve to eliminate pressure spikes that occur under high-rpm/boost lift-throttle situations. The vacuum/boost operated valve also allowed excess flow from the blower to escape under light-throttle, cruise conditions.

New from TorqStorm, the supplied kit featured this low-profile carb bonnet. The design will certainly help with tight hood clearance applications.

Run on the dyno with the TorqStorm supercharger kit, the supercharged Chevy produced 559 hp and 501 lb-ft of torque.

The 5.0L Ford also received an intake swap. The Funnel Web run in part three was replaced by this polished Eliminator intake from Speedmaster.

Both the Ford and Chevy were run in supercharged trim with this dedicated blow-though carburetor from Carb Solutions Unlimited.

Both the Ford and Chevy received sufficient spark energy from MSD distributors combined with a 6AL ignition amplifier.

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

The TorqStorm kit supplied for the Ford positioned the blower on the passenger’s side. Installation was quick and easy, requiring that we bolt the mounting bracket to the cylinder head.

Next, we secured the blower/tensioner mount to the cylinder head bracket.

We then installed the centrifugal supercharger in place using the supplied Allen-head retaining bolts.

Both the Ford and Chevy were run with the same supercharger and 3.25-inch blower pulley.

Run in anger under boost, the supercharged Ford produced 619 hp and 537 lb-ft of torque, but know that this is well within splitting territory of the thin-wall, factory 5.0L block.

Carbureted 305 Chevy-NA vs TorqStorm Boost

After replacing the single-plane intake in part three, we ran the 305 Chevy with a dual-plane, Performer RPM Air Gap intake with positive results. Run 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. After installation of the TorqStorm supercharger, the power output jumped to 559 hp at 6,000 rpm and 501 lb-ft of torque at 5,500 rpm. This represented a gain of 47% over the normally aspirated combination.

Carbureted 302 Ford-NA vs TorqStorm Boost

The 5.0L Ford was given the same treatment, by replacing the Funnel Web intake with a dual-plane, Eliminator from Speedmaster. Run 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. After installation of the TorqStorm supercharger, the power numbers jumped to 619 hp at 6,200 rpm and 537 lb-ft of torque at 5,900 rpm. The TorqStorm increased the power output of the little Ford by over 46%, making it consistent (percentage wise) with the gains offered on the Chevy.