The Xtreme Energy cam featured a relatively wide 112-degree lobe separation angle (LSA), something that helped improve the idle and broaden the power band. Since our supercharged stroker would easily exceed the strength of the production block, we erred on the mild side of cam timing to improve idle quality and drivability. If you have more than enough power, why not have it idle like a stocker? As mentioned, Comp Cams also supplied the necessary hydraulic roller lifters, spider hold-down assembly, and hardened pushrods. Comp also supplied aluminum 1.6- ratio roller rockers. The 331 stroker short-block was finished off with Fel Pro oil pan and front cover gaskets, a 28-ounce balancer, and Melling's HV oil pump (making sure to include an ARP HD oil pump drive).
Next, it was time to address our cylinder head needs. While our combination was purposely kept on the mild side, we stepped up big time on the cylinder heads. Combining a mild cam and high-flow heads yields a much better power curve than the other way around. Knowing this, we installed a set of CNC-ported RHS Elite heads on the stroker. The Pro Elite heads offered exceptional flow thanks to CNC-ported 205cc intake ports, a multi-angle valve job, and CNC combustion chambers. Further improving flow was the fact that the 20-degree heads were assembled with a 2.055/1.60-inch stainless-steel valve package. The heads included rockers studs and guideplates for the 1.6-ratio roller rockers, and the heads were secured to the stroker using Fel Pro 101-2 head gaskets and 7/16-inch ARP head studs. The heads were topped off with an Edelbrock Performer RPM Air Gap intake and new Mighty Demon carburetor.
The carburetor worked well on both the naturally aspirated and supercharged combination. An MSD billet distributor, Meziere electric water pump and 1-3/4-inch Hooker headers completed the normally aspirated combination. Exhaust from the Hooker Super Comp (Fox chassis) headers was channeled through 18-inch collector extensions.
The 331 stroker would prove to be plenty powerful in normally aspirated trim, but the low-compression, mild-cammed Ford combination was built specifically for boost. Boost in this case came from a Paxton Novi 1200 supercharger supplied as part of its carbureted Mustang kits. The kit came complete with the supercharger (you can also choose a slightly more powerful Novi 1500), carb enclosure, blower mount, pulleys and fuel system. We opted for the driver-side mount, but the carb kit is also available with the blower mounted on the passenger side a la 5.0L EFI motors. We relied on a 750 Mighty Demon carburetor set up with a 89/91 jet and 0.028 air bleed combination.

5 The mild Comp Xtreme Energy...

5 The mild Comp Xtreme Energy cam was combined with a dual-plane RPM Air Gap intake. The dual-plane intake was designed to optimize power production in the streetable rpm range (below 6,500 rpm).

6 We installed a new Mighty...

6 We installed a new Mighty Demon carburetor in the Paxton carb enclosure. Minor tuning resulted in excellent power and driveability.

7 The supercharged stroker...

7 The supercharged stroker received boost from a carbureted Paxton supercharger kit. Our kit featured everything needed to dramatically improve the power output of any carbureted small-block Ford.
The Paxton Novi 1200 was installed using a 7-inch crank pulley and 3.33-inch blower pulley, which produced a peak boost pressure of 9.4 psi at 6,000 rpm. Naturally the curve was still rising, but in deference to the stock block, we kept engine speed and boost to a minimum. It is possible to adjust the boost level provided by the blower with changes in blower and/or crank pulley size. With our static compression ratio below 9.0:1, the boost level was easily run on pump gas.
Before running the Novi 1200, the stroker was first treated to a break-in cycle then run in normally aspirated trim to establish a baseline. After jetting and timing sweeps, we ran the motor from 2,500 to 6,000 rpm in an effort to demonstrate the power gains offered in the streetable rev ranges. In normally aspirated trim, the low-compression 331 produced 392 hp at 6,000 rpm and 386 lb-ft of torque at 4,400 rpm. These were respectable numbers considering the mild tune.
After installation of the Novi 1200, the power numbers jumped considerably. Run at a maximum boost of 9.4 psi, the supercharged 331 produced 617 hp at 6,000 rpm, and 561 lb-ft of torque at 5,200 rpm. True to form, the carbureted Paxton kit added over 200 hp and 200 lb-ft of torque--all on pump gas.
The carb enclosure demonstrated its worth, offering not only plenty of power and a safe air/fuel mixture, but also impressive idle and part-throttle characteristics. A carburetor can never match a dedicated EFI system for optimum fuel control under every combination of load, throttle angle, and engine speed, but it performed every bit as well as your typical NA carbureted motor, and did so without an expensive electronic fuel injection kit.

8 Depending on your application,...

8 Depending on your application, the supercharger can be mounted on the driver or passenger side of the engine. We chose a driver-side supercharger mounting location.

9 Our kit featured a Novi...

9 Our kit featured a Novi 1200 supercharger, but other superchargers are available. The Novi 1200 was capable of supporting over 750 hp, so it was more than enough supercharger for our application.

10 Boost is a function of...

10 Boost is a function of the blower speed relative to engine speed. We chose to start our testing with a 3.33-inch blower pulley.

11 The 3.33-inch blower pulley...

11 The 3.33-inch blower pulley was combined with a 7.0-inch crank pulley, which resulted in a peak boost pressure of 9.4 psi at 6,000 rpm.

12 Belt tension was provided...

12 Belt tension was provided by a fixed tensioner. After making a few runs on a new belt, it is a god idea to retighten the belt to take up the slack from belt stretch.

13 Paxton offered self-contained...

13 Paxton offered self-contained superchargers, but our kit featured a supercharger that required a dedicated oil feed and return. We tapped into the oil feed line used for the stock sensor to provide oil to the supercharger.

14 The oil drain required...

14 The oil drain required drilling and tapping (or welding) the oil pan. The kit comes with a punch and tap to perform the task on the motor (in the car), but since our motor was still on the engine stand, we removed the pan to perform the surgery.

15 With everything hooked...

15 With everything hooked up and tuned to perfection, the Paxton supercharger increased the output from 392 hp and 386 lb-ft. of torque at 4,400 rpm to 617 hp at 6,000 rpm and 561 lb-ft of torque at 5,200 rpm. The boost and power curves were still climbing but we purposely limited power production and engine speed to keep the stock block in one piece.