How do you make 900 horsepower for your project vehicle?
Should you go LS or BBC? Should you go turbo or blower?
There are so many questions, and truth be told, there are only good answers! Let’s check out two different routes for exceeding 900 hp, both of which originated from the local wrecking yard, starting with a Gen. 6 454 BBC.
The Supercharged Big Block
When it comes to making big power, it is hard to argue with the combination of a big block and boost! (Image/Richard Holdener)
The 1998 Gen. 6 454 was pulled from a local wrecking yard and (as is our custom) run in stock trim to verify it was indeed a viable test mule. Though we have run them with the factory EFI setup in the past, we ditched that in favor of simple and effective carburetion (BBC fans are carb fans—just ask Steve Brule!).
The BBC was run with a dual-plane manifold, 650 carb (I can hear the BBC folks scream from here), and MSD distributor. In this manner it made 375 hp or so, which jumped to 425 hp and 480 lb.-ft. of torque after we replaced the stock hydraulic roller cam with a Comp XR276HR cam (0.510 lift, 224/230 degree duration, and 112 degree LSA). With 425 hp, we were less than half way to our goal of 900 hp—but fear not, a Vortech supercharger was invited to the party!
To reach our goal of 900 hp, we installed a Vortech YSI supercharger (capable of four-digit power levels).
We also upgraded the 650 carb (BBC folks are happy now) with a larger (but more importantly) blow-through 850 carb from Carb Solutions Unlimited. The CSU blow-through carb allowed us to dial in the A/F curve under boost.
Knowing we would be running elevated boost levels (above 15 psi), we opted to include an air-to-water intercooler (yes, we also tested it non intercooled). The intercooler dropped temps by 130 degrees! Once tuned, the combination produced peak numbers 848 hp and 761 lb.-ft. of torque at 17.7 psi.
The final mod was to replace the stock, iron Gen. 6 heads with aluminum Race Rite cylinder heads from Brodix. The Brodix heads lowered the compression (102 vs. 120cc chambers) but offered an additional 100 cfm of flow.
Despite the lower compression, the head swap pushed peak power up to 904 hp and 802 lb.-ft. of torque. Every bit as important, the boost dropped from 17.7 psi to 16.4 psi, meaning more power at less boost—always a win/win!
The Turbo LS
Blown big blocks are awesome, but turbo LS motors know how to party too. Case in point, this 900+ hp junkyard 5.3L.
Like the Gen. 6 454, the all-aluminum L33 5.3L also came from the local wrecking yard (the very same one as the 454). It is always a good day when you can score either a 6.0L or aluminum 5.3L (no, I’ve never found an aluminum 6.0L or 6.2L in a yard).
After liberating the motor from the yard, it was taken directly to Westech and prepped for dyno use. We removed all the accessories (but kept them for a later accessory test), replaced the factory manifolds with headers, and installed 1,000cc injectors. The big injectors were installed at this point in preparation for later boost.
After fresh oil and a filter, we ran the motor in stock trim to the tune of 365 hp and 389 lb.-ft. of torque.
The next step was to replace the factory springs with a dual-spring kit from BTR in anticipation of later cam testing (BTR, Summit Racing, Cam Motion, etc.). The dual springs were not needed for the 0.550 lift RHP Low Buck Truck cam (0.550 lift, 212/22x, 107 LSA), but equipped with that cam and a TBSS intake and 92mm throttle body, the power output of the 5.3L just missed the 440 hp mark (439.5 hp) with 423.5 lb.-ft. of torque. Like the junkyard BBC, we were less than half way to the 900 hp mark.
The cure to making big hp was obviously boost, so we added a turbo system to the junkyard 5.3L. The long-tube headers were replaced by a set of stock truck exhaust manifolds. The manifolds were reversed (facing the front of the motor) to feed a custom Y pipe. The Y pipe joined the exhaust from both banks to feed the single turbo. The Y pipe also featured a pair of flanges to mount dual Turbosmart 45mm Hyper Gate waste gates. Boost control was ensured with the dual gates.
The Y pipe fed into a single 3 inch V-band which could be used with an adapter to mount T3, T4, or even T6 turbos—like the popular S475 unit from Summit Racing—but the RHP G42 featured a 3 inch V-band turbine housing.
The G42 was capable of supporting 1,200 hp, so it was just getting started on this 900 hp 5.3L. Boost from the turbo was run through an air-to-water intercooler (dyno water like the BBC). Running a peak boost of 15.5 psi on E85 fuel, the turbo 5.3L produced 914 hp and 904 lb.-ft. of torque.
Now the question is, which one would you choose? The answer is there is no bad choice here!
The graph illustrates not only what happens when you add a Vortech Supercharger to a mild, Gen. 6 454 from the junkyard, but also what happens when you replace the stock iron cylinder heads. Equipped with a mild Comp (XR276HR) cam, dual-plane intake and Holley carb, the Gen. 6 454 produced 425 hp and 480 lb.-ft. of torque. This jumped to almost 850 hp after the installation of the YSI supercharger. After replacing the stock iron heads with Brodix Race Rite alum heads, the power output jumped to 904 hp. Every bit as impressive was the fact that the increase in power came despite a sizable drop in compression from the larger chambers (102 vs 120cc) on the aluminum heads. (Dyno Chart/Richard Holdener)
The junkyard 5.3L was snatched from a local wrecking yard and equipped with a Low Buck Truck cam and BTR springs from RHP. The upgrades also included a set of 1,000cc injectors, a TBSS intake and FAST 92mm throttle body. Run on the dyno with long-tube headers and a Holley HP, the NA 5.3L produced 440 hp and 424 lb.-ft. of torque. After installation of the RHP G42 turbo, intercooler, and E85 fuel, the power output jumped to 914 hp and 905 lb.-ft. of torque at 15.5 psi. (Dyno Chart/Richard Holdener)
Prior to running on the dyno, the Gen. 6 454 was treated to a cam upgrade. The Comp XR276HR-13 cam offered 0.510 lift, a 224/230 degree duration split, and a 112 degree LSA. (Image/Richard Holdener)
Run on the engine dyno with a dual-plane intake, 650 carb, and long tube headers, the NA 454 produced 424 hp and 480 lb.-ft. of torque. (Image/Richard Holdener)
To step the power up, we added a Vortech YSI centrifugal supercharger kit. The cog pulley eliminated any chance of belt slip. (Image/Richard Holdener)
Because we were looking to double the power output with boost, we added this air-to-water intercooler. (Image/Richard Holdener)
The Vortech supercharger was teamed with this CSU 850 blow-through carb and dedicated carb bonnet. (Image/Richard Holdener)
Run on the dyno with race fuel, the Vortech supercharged 454 produced 848 hp and 761 lb.-ft. of torque at 17.6 psi. (Image/Richard Holdener)
Looking to step up the power while simultaneously dropping the boost, we removed the stock, iron Gen. 6 cylinder heads. (Image/Richard Holdener)
The heads were replaced with aluminum Brodix Race Rite BBC heads. Compared to the stock, iron Gen. 6 heads, the Brodix Race Rite heads offered and additional 100 cfm worth of flow (345 vs. 245 cfm). (Image/Richard Holdener)
Run with the Brodix aluminum heads, the peak power output jumped to 904 hp and 802 lb.-ft. of torque at a slightly lower 16.4 psi. The aluminum head swap reduced the chance of detonation, lowered the compression (by nearly one full point), and added a bunch of power. (Image/Richard Holdener)
The 900 hp 5.3L LS test motor was also a junkyard jewel. The aluminum L33 was disassembled and extra ring gap added prior to boost. (Image/Richard Holdener)
Like the BBC, the LS received a cam upgrade in the form of a Low Buck Truck (0.552 lift, 212/22X degree duration, and a 107 LSA) from Richard Holdener Performance (RHP). (Image/Richard Holdener)
For this test, the L33 was run with the factory 799 aluminum heads. (Image/Richard Holdener)
The heads were treated to a set of BTR dual spring upgrade. The dual springs were not necessary for the 0.550 lift cam, but they would come into play with later (larger) cams. (Image/Richard Holdener)
The 5.3L L33 was equipped with a TBSS intake and 92mm FAST throttle body. Run NA, the 5.3L produced 440 hp—OK, technically 439.5 hp. (Image/Richard Holdener)
The turbo system employed on the engine dyno featured a pair of stock truck manifolds reversed to face forward. (Image/Richard Holdener)
The truck manifolds fed a custom Y pipe equipped with provisions for dual Turbosmart waste gates. (Image/Richard Holdener)
The Y pipe also featured a V-band flange to accept this V-band G42 RHP turbo capable of supporting 1,200 hp. (Image/Richard Holdener)
Run on the dyno with E85 fuel at 15.5 psi of boost, the turbo 5.3L produced 914 hp and 905 lb.-ft. of torque. (Image/Richard Holdener)
