In the last segment of our series, we began our look inside the honking 1,100-plus HP 4.0-liter Whipple blown 427 LS. If you point your browser back to part three, you’ll recall it shares a large number of components with the 2.9-liter (blown) version; however, there are several key differences.
The big blower is obvious, but in order to keep pace with the big volume twin-screw supercharger, the cylinder heads are upgraded. Here, the base head is a CNC-ported Brodix BR7. These 6-bolt, 12-degree cylinder heads are the Brodix take on Chevy’s LS7 casting. The BR7-BS273 is engineered to accept a big valve spring (up to 1.650 inches in diameter). Intake valves measure 2.250 inches in diameter and the exhaust valves measure 1.614 inches. The head flows in excess of 415 CFM at 0.700-inch lift.
That’s not the end of it either. Brodix has recently unveiled two new BR7 heads designed specifically for turbos or big blowers such as the 4.0-liter Whipple. Those heads have port volumes of 285 and 300-cc’s respectively. And they move prodigious amounts of air, with a lot of attention given to the exhaust side of the equation. You’ll have to speak directly with the folks at Borowski regarding these heads.
Brodix isn’t the only head option for the big power LS. Borowski also offers a custom All Pro LS7-style cylinder head package. It’s engineered to accept shaft rockers. The CNC ported head is completed on their Newen cylinder head machine (see part 2 of our series for a brief description), and it’s fitted with Xceldyne 5/16-inch stem titanium Intake and Manley Extreme Duty Inconel exhaust valves, PAC Racing dual drag race 1300 series valve springs (Coil Bind: .960, 780 lbs./in) and PAC Racing ‘Standard 8’ valve locks, along with matching PAC Racing retainers and spring cups. These heads are well suited to big boost applications in that they go through a HIP process to increase strength – plus, they have a minimum deck thickness of ¾-inch (in some areas they are almost an inch thick). Equally important is the fact that this head (and others) can be custom tailored to your exact combination.
Upstairs, the big 4.0-liter twin-screw supercharger fits under most cowl induction style hoods without modifications. McCaul notes that compared to Whipple’s 2.9L version, it is able to generate substantially more boost (approximately 19 psi vs. 13 psi). The high efficiency reduces heat generated, compressing the inlet air, plus the integral inter-cooler is very effective at maintaining a low manifold air temperature, allowing engine designs with higher compression ratios, more timing or both.
With the big boost capabilities in mind, it’s no secret this thing can really crank up the dial on the dynamometer. With a load of C16 in the fuel cell, Borowski’s first 4.0-liter Whipple blown 427 nailed down a peak power number of 1,140 horsepower and a whopping 1,035 foot-pounds of torque. That’s a bunch and you’ll need a pretty good car to handle it!
Optionally available is a complete billet serpentine drive setup. According to Ken: “Our custom serpentine systems come with all high-end accessories. No skimping! The 225-amp alternator will easily handle the electronics typical for modern resto mod. The PS pump can be ordered either with its own reservoir or with a remote reservoir and fittings for hooking up your Hydratech brake boosters. One critical design element often given insufficient attention is the harmonic dampener. We use an ATI Super Damper with rubber durometer matched to power so as to protect the engine’s operation and longevity. A harmonic balancer suitable for a 600 HP NA engine is not going to properly protect a max-effort supercharged engine.”
“When you’re thinking blower, the serpentine system is critical to the operation of any supercharger as it relies on the belts to spin it. Our Whipple supercharged LS engines push out over 1,000 HP and that really puts this accessory drive to the test. In keeping with the performance of the engine, our billet design is strong and compact to avoid deflection of the brackets. That compact design allows for an easier install while creating a better look under the hood. Finally, the serpentine system and matching valve covers are also available upgraded to a polish finish.”
It’s good to know you can buy this engine turn-key; however, Borowski also offers it as a long block (no blower) or even a short block assembly. They even offer a “set-to-kill” example that can handle huge boost. You only have to ask.
But that’s not the end of it. Borowski has a wide (wide!) range of engine configurations available for LS and more traditional applications. For example, they offer aluminum and iron LS short blocks for naturally aspirated or forced induction applications. They also build Ford small blocks, traditional small block Chevys, big block Chevys and even restoration engines.