Words And Photos: Richard Holdener

Back in Level Up Part 1, we took a look at some small block performance packages that ranged from mild to slightly wild. Starting with a 300 horsepower combo, we worked our way up through 400 horsepower right to a small-block build up that yielded an honest 500 horsepower. As we pointed out, small block build ups mean different things to different people. Not everyone wants or needs a dedicated race motor, nor is everyone satisfied with something stock. The vast majority of us are somewhere in between, so we decided to illustrate not one but several build ups that covered different power levels. Having previously illustrated the 300, 400 and 500-horsepower combos in part 1, we decided to keep things going in part 2 with 600, 700 and 800-horsepower small blocks. You might think these mouse motors represent a serious departure from the milder combos in part 1, but the presence of power adders allow the combinations to be every bit as streetable, yet provide amazing performance. Such are the benefits of increased displacement, nitrous oxide and superchargers. Check out these serious small block packages or combine them to Level Up for even more power.

Level 4: 600-HP 427 Stroker  

Short Block-Speedmaster 4-Bolt block, Stroker crank and rods, Probe Pistons
Heads: AFR 220 Race Ready, 2.10/1.60 Valves, 320 cfm
Cam: COMP 292XFI HR13-.584/.579 lift split, 242/248 duration split and a 113-degree
Rockers: COMP Ultra Pro Magnum
Intake: Ported Speedmaster Single Plane Shoot Out
Carb: Holley 950 Ultra HP
Exhaust: 1 3/4-inch Headers

The key to building a streetable, 600-hp small block is to build it big, add plenty of air flow and cam timing, then top it with a good carb and intake. Getting a small block to produce 600 horsepower isn’t terribly difficult but getting one to do so AND be streetable is much more so. Looking at specific outputs (hp produced per cubic inch of displacement), we see that a 600-hp 350 equates to 1.709 horsepower per inch. That is a very high specific output and one that requires a very wild cam which in turn pushes the peak power output high into the rpm range. Unfortunately, this also minimizes the drivability down low, as a cam optimized for power production at 7,500 rpm (or above) will be less than optimized down at the usual cruising speeds of 2500-3000 rpm, to say nothing of an idle speed below 1,000 rpm.

If we step up displacement to 427 inches, we reduce the specific output required to just 1.405 hp/inch (equal to a 491-hp 350). In doing so, we have a motor that will produce peak power much lower than the smaller (and wilder) 600-hp 350 combo. This 427 build up did just that, as the stroker short block from Speedmaster and Probe combined with a healthy COMP hydraulic roller cam, a set of AFR 220 Race Ready heads (flowing 330 cfm) and a ported single-plane intake to produce 605 hp at 6,500 rpm and 577 lb-ft at 5,200 rpm. Torque production from the stroker exceeded 550 lb-ft from below 4,000 rpm to 5,600 rpm, something not possible with a smaller displacement combo.

Level 5: 700-HP Nitrous-Injected 383 Chevy

Short Block-Late 350 Chevy block, Scat stroker crank and rods, Flat-Top JE Pistons
Heads: AFR 195 Eliminator 2.05./1.6 valves 65-cc chambers
Cam: COMP Hydraulic Roller 292XFI (.584/.579 lift, 242/248 duration, 113 LSA)
Rockers: COMP Cams Magnum 1.5-Ratio Roller
Intake: Edelbrock Performer RPM Air gap
Carb: Holley 950 HP
Exhaust: 1 3/4-inch Headers
Nitrous-NX Adjustable Plate (150-HP Jetting)

Stepping up to 700 horsepower, we combined additional cubic inches with some chemical supercharging. While nitrous oxide can be applied to any motor, including a bone-stock small block, heavy doses are best used with a combination designed to take the extra power. To reach 700 horsepower, we started out with a healthy stroker combination that offered impressive power even before we engaged the nitrous. The 383 stroker short block was teamed with AFR 195 Eliminator heads, a high-lift XFI cam from COMP Cams and a Holley/Edelbrock induction system.

This allowed the 383 to thump out nearly 550 hp before engaging the nitrous. Adding the Nitrous Express plate to the mix with 150-HP jetting stepped things up considerably, with peak numbers of 732 hp and 730 lb-ft of torque. We made sure to maximize the power potential of the nitrous kit by heating the bottle to ensure a bottle pressure over 900 psi. We dialed in the air/fuel mixture with carb jetting and pulled 6 degrees of ignition timing upon activation of the nitrous.

Level 6: 800-HP Supercharged 400 Chevy

Short Block-Dart block, Scat stroker crank & rods, Mahle Flat-Top Pistons
Heads: TFS Super 23 230 Heads, CNC porting, 2.08./1.6 valves, 329 cfm
Cam: Crane Solid Roller (.670/.625 lift, 260/268 duration, 108-degree LSA)
Rockers: COMP Roller 1.5
Intake: Weiand Blower
Carb(s): Dual Holley 950 Ultra HP
Exhaust: 1 3/4-inch Headers
Supercharger: Weiand 8-71

Looking to up the power ante to 800 horsepower, we once again combined displacement with a power adder. Rather than go with a big shot of nitrous, we opted for some boost from a serious supercharger. The displacement came from stuffing a 3.75-inch stroker crank into a 4.125-inch Dart block. Given the power level, a Dart block was considered necessary. The Scat forged crank and rods were combined with a set of Mahle flat-top pistons to produce 400 cubic inches. The stroker short block was then combined with a COMP XR294HR cam, a set of CNC-ported TFS Super 23 230 heads and run in normally aspirated trim with a Dart single plane intake and single Holley 950 Ultra HP carb.

The stroker combination produced over 570 hp and nearly 500 lb-ft of torque, but the real power came after the installation of the Weiand 8-71 supercharger. During testing, we snuck up on the eventual maximum boost pressure, but the combination of a 57-tooth crank pulley and 59-tooth blower pulley resulted in 11.7 psi at 6,800 rpm. Feeding the supercharged monster was no less than a pair of 950 HP Holley carbs. Run in anger, the supercharged stroker produced 819 hp at 6,800 rpm and 667 lb-ft of torque at 5,600 rpm. The power curve was still climbing rapidly at our shut-off point, but it is hard to argue with any 800-hp small block.

Sources

ARP
arp-bolts.com

Air Flow Research
airflowreaserch.com

COMP Cams
compcams.com

Dart
dartheads.com

Edelbrock
edelbrock.com

Holley/Hooker/Weiand
holley.com

JE Pistons
jepistons.com

Lucas Oil
lucasoil.com

MSD
msdignition.com

Speedmaster
speedmaster79.com

Trick Flow Specialties
trickflow.com