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Chevy Small Block Part II - Show Us What You're Made Of

Part II-Vrbancic Brothers Racing 383 Blown Stroker

By Dakota Wentz

What do you know; it's that time already. Just like we promised, here's part two of the Vrbancic Brothers Racing pump-gas blown 383 stroker. Oh yeah, this time we brought some friends along. What friends you ask? How about numeric friends? The dyno results are in. We're pretty sure you won't be disappointed.

Before we get started, lets have a little review. For those of you not familiar with Part I, the goal for this engine was simple. Get 700 horses out of a big-inch small-block with a supercharger while still having a streetable motor. What's the definition of streetable? In this case something that would idle at a stoplight, and could be filled up with 91-octane at the gas station. Also if you're wondering about the compression, it's 8.8:1.

The build was based on a World Products Motown race-prepped 350 block that is built to handle the high-combustion pressures of a supercharger. The supercharger chosen to complement the block was a D1-SC centrifugal supercharger from ATI Procharger. Rounding out the motor is Holley Systemax parts, including a matched set of intake manifold, heads, and valvetrain along with an entire rotating assembly. Various parts from other performance companies topped it all off.

Once the motor was finished, it was time to see what she was made of. The 383 took a trip (of about 15 feet) to the Vrbancic Brothers Racing state-of-the-art DTS dyno. Arco 91-octane gas was the choice of fuel for the application, based on the fact it's the cheapest high-octane gas in the So Cal market. The 383 was placed on the dyno with the Carb Shop prepped Holley CF 750 carb jetted with 74s in the primaries and 86s in the secondaries. For the initial dyno run the timing was set at 28 degrees. The first pull posted more than respectable numbers. The 383 cranked out 685.9 hp and 600.3 ft-lb of torque at 6,000 rpm with 11 pounds of boost. The motor even pushed out 462.8 ft-lb of torque at 2,800 rpm! Can anyone say burnout? Any streetcar would light 'em up with that kind of power; however, the goal was 700 hp.

For the second run, Bob Vrbancic knew some changes were necessary to climb into the 700 range. Vrbancic Racing decided to change the primaries from 74s to 72s and switch to 84s, instead of 86s, in the back. Also to help aid in the quest for 700 hp, Red Line 50WT synthetic race oil was added to the mix. The timing was also changed to 34 degrees. Included in the MSD ignition is a boost retard control. The retard control allows users to instantly retard the boost one to three degrees. Bob decided to retard the boost one degree, which calculates out to 1-degree retard per pound of boost.

For the second pull Vrbancic decided to rev the motor higher. This time the 383 would be revved to 6,100 rpm instead of 6,000 rpm. As it turned out the changes made were just what the motor needed. The second pull pumped out 35 more horsepower and 20 more ft-lb of torque. That's right the motor jumped from 685.9 hp to 720.3 hp and the torque went from 600.3 to 620.1 ft-lb. Not bad! The boost also increased to 13.2 pounds. I guess I'd put that in my car, but only if I had to!

Considering the fact we know how hard it is to get a motor setup that will suit your needs, this might be able to help you. Vrbancic Brothers Racing has given us an entire breakdown of nearly every part in the 383. So if you're interested in duplicating a copy of the 383 for yourself check out the chart below. Or if you're just curious to see what it took to produce those kinds of numbers, knock yourself out.

PART Manufacturer Part Number
Block: World Products Motown 08411
Oil Pump Melling 10550
Crank Lunati AJ111/L41048
Rods Lunati Pro Billet 6.000 LAD 2
Pistons Lunati 131UB753
Rings Lunati P 14035
Main Bearings King MB 1542 HP
Rod Bearings King CR 848 HP
Cam Bearings Sealed Power 1235M
Cam Shaft Lunati 50199LUN
Timing Set Lunati 93115
Crank Dampener Professional Products 90000
Head Studs ARP 134-4001
Water Pump Meziere WP 401U
Cylinder Heads Holley 300-552
Hydraulic Roller Lifters Lunati 7281LUN
Pushrods Lunati 83132
Billet Timing Pointer B&B 61910
Roller Rocker Arms Lunati 84146 (1.5)
Roller Rocker Arms Lunati 84149 (1.6)
Lock Nuts/Roller Rockers Lunati 84380
Supercharger Accessible Technologies Inc. D1-SC centrifugal
Intake Manifold Weiand
Ignition MSD
Headers Hooker
Carburetor Carb Shop Holley 80528-52 BT
SOURCES
Accessible Technologies, Inc.
14801 W. 114th Terr
Lenexa
KS  66215
Meziere
8-00/-208-1755
meziere.com
Automotive Racing Products
1863 Eastman Ave.
Ventura
CA  93003
800-826-3045
www.arp-bolts.com
MSD Autotronic Controls Corporation
El Paso
TX  79936
915-857-5200
www.msdignition.com
Concept Powder Coating
8747 Flower Rd.
Rancho Cucamonga
CA  91730
Professional Products
Hawthorne
CA
3-23/-779-2020
professional-products.com
Hooker Headers Sealed Power Engine Parts Federal-Mogul Corporation
26555 Northwestern Hwy.
Southfield
MI  48034
Holley Vrbancic Bros. Racing
N/A
customcarbs.com
King Engine Bearings, INC.
371 Little Falls Rd.
Cedar Grove
NJ  07009
Weiand A Holley Performance Brand
1801 Russelville Rd.
P.O.Box 10360
Bowling Green
KY  42102
Lunati
4770 Lamar Ave.
Memphis
TN  38181
901-365-0950
www.lunaticamshafts.com
World Products
Ronkonkoma
NY
6-31/-981-1918
www.worldcastings.com
Melling Tool Company
PO Box 1188
Jackson
MI   49204
By Dakota Wentz
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