383ci Stroker Small-Block Engine Build - Second Chance 383
A Stroker Small-Block Combo For the Street
From the April, 2011 issue of Chevy High Performance
By Sean Haggai
Photography by Sean Haggai
Small-block engines have a resiliency like no other. Their simplistic design is easy to maintain and when treated correctly, can withstand years of abuse in street or race form. Almost any solid short-block can be reincarnated for other duties with fresh bearings, a new valvetrain, and a bigger set of lungs with a matching manifold. And that’s exactly what we did. We got our hands on a fully built, low-compression short-block with four-bolt mains, a Scat crank with 5.700-inch H-beam rods, and a set of Ross dished pistons. Built some years back, originally with a Weiand 177 supercharger, the 383ci mill produced 615 hp on the cheap juice to make the perfect weekend-warrior bracket racer for a ’72 Camaro.
While combinations are available to fit a wide variety of budgets or applications, street longevity is where it’s at for us. It’s also where you’ll see the most return for the money. This particular 383ci powerplant was beginning its second life, and street duties were the new priority. The blower, along with the blower-spec’d camshaft (114 lobe center), rockers, lifters, and cylinder heads were all pulled to create a naturally aspirated street-specific motor. This time around, we went with a custom-grind, higher-lift COMP solid-roller camshaft with 242/248 degrees duration at 0.050 inch and 0.571/0.577 inch of lift. We also completed the valvetrain with a set of roller rockers and solid-roller lifters, too. Our set of aluminum Patriot Performance cylinder heads were outfitted with 2.02-/1.60-inch intake/exhaust valves and 0.575-inch-lift springs and are CNC-machined to flow 215cc right from the box! To up the ante, we even tested a single- and dual-plane Weiand manifold. To our surprise, the single-plane made less average power than the dualproof that more isn’t always better.
We followed the power-hungry Vrbancic Brothers out of Ontario, California’s The Carb Shop as the pair put together a 383ci combination that would satisfy the most insatiable diet for grunt. We got down and dirty by cleaning the tops of each piston and the deck, and began adding the new camshaft and top end. We illustrate the parts used and how much power our 383ci put down on the dyno at Vrbancic Brothers’ engine dyno.
Our foundation for this top...
Our foundation for this top end consisted of a one-piece rear main seal block with a Scat crankshaft, H-beam 5.700-inch rods, Ross pistons, Total Seal rings, and Clevite bearings. Originally, this engine was built to support a supercharger and with the 76cc cylinder heads, compression sat around 8.5:1. On the engine stand at Vrbancic, we peeled away all the old parts including the entire valvetrain and cylinder heads.
To prep the deck surface,...
To prep the deck surface, we brought each piston up to top dead center and cleaned the tops of each piston along with the deck. We used some solvent with a Scotch-Brite pad to remove the carbon and old gasket material.
With the old components out,...
With the old components out, George Vrbancic went ahead and prepped the new, higher-lift camshaft with lube. Paying close attention as to not gall the cam bearings, we slid the new cam in along with the new timing set from COMP.
The degree wheel was locked...
The degree wheel was locked in placed and George dialed the camshaft in at 110 degrees. Look forward to degreeing a camshaft in a future issue.
Patriot Performance’s Freedom Series line of cylinder heads cover every runner volume from 195 to 225 cc. For this particular build, we went with the 215cc runners and ordered a custom 60cc combustion chamber to bump up compression. Patriot’s small-block cylinder heads were designed with countless hours of R&D and have 100 percent CNC-ported intake and exhaust runners. These heads were assembled with 2.02-/1.60-inch intake/exhaust stainless steel valves, 0.575-inch-lift springs, steel retainers, machined locks, viton seals, 3/8-inch studs, and guideplates. Bronze guides are also included with a five-angle valve job and hand blending of the bowls.
Combustion Chamber (custom) 60 cc
Intake Runner 215 cc
Exhaust Runner 65 cc
Intake Valve 2.02 inches
Exhaust Valve 1.60 inches
Max. Valvespring Lift 0.650 inch
Spring Pressure Closed 135 pounds at 1.800 inch
Spring Pressure Open 375 pounds at 1.225 inch
To ensure our build would...
To ensure our build would go smoothly, we enlisted the help of a 7/16-inch tap to chase the threads of each cylinder head bolthole in the deck. We added a dab of oil to the tap for each hole to remove any rust or debris.
Spinning the engine upside...
Spinning the engine upside down allowed us to install our one-piece Fel-Pro oil pan gasket. Bob Vrbancic meticulously fit the gasket into the bottom of the timing cover and lined up the boltholes.
With the Milodon oil pump,...
With the Milodon oil pump, pickup, and shaft already installed, we dropped down the oil pan and even used the older oil pan fasteners to bolt it all down.
1. For testing, our 383 utilized a combination of PerTronix distributor and Flame-Thrower coil. The Flame-Thrower plug-and-play billet distributor offers the Ignitor III electronic ignition module and a 6061-T6 polished billet housing. Plus, a built-in LED allows rev limiter setting.
2. COMP’s solid roller camshaft with a small base circle spec’d out with 0.571-/0.577-inch intake/exhaust and 242/248 degrees intake/exhaust of duration at 0.050 inch. Our lobe separation was 110 degrees.
3. Both manifold testing used a set of Vrbancic dyno headers with 17/8-inch primary tubes.
4. Holley’s Street Avenger offers a trouble-free carburetor that’s calibrated to give you performance without all the headaches. This 870 featured a tunable metering system, fuel filters in the primary and secondary fuel bowls, center-hung floats, external float adjustments with sight plugs, electric choke, emissions accessory ports, adjustable secondaries, power valve saver, and dual-feed conversion fuel line.
5. Oil control was handled by a Milodon low-profile deep sump oil pan with side kick outs. Inside sat a diamond stripper windage tray to keep splash at a minimum.
|CAM SPECS |
|Manufacturer ||COMP Cams |
|PN ||12-000-8 |
|Type ||Solid roller |
|Valve Lift ||0.571/0.577 inch, intake/exhaust |
|Duration at 0.050 ||242/248, intake/exhaust |
|Lash ||0.016/0.018, intake/exhaust |
|Lobe Separation Angle ||110 degrees |
|DYNO DETAILS |
|Size ||383 ||Size ||383 |
|Intake ||Street Warrior dual-plane ||Intake ||Team G single-plane |
|Headers ||tk ||Headers ||tk |
|Advance ||36 ||Advance ||40 |
|Fuel ||91 ||Fuel ||91 |
|Carb ||870 cfm ||Carb ||870 cfm |
|Jets ||84/86 ||Jets ||84/86 |
|Max. Torque ||474 at 4,700 rpm ||Max. Torque ||475 at 4,800 rpm |
|Max. Power ||490 at 5,800 rpm ||Max. Power ||493 at 6,100 rpm |
|Avg. Torque ||455 ||Avg. Torque ||444 |
|Avg. Power ||408 ||Avg. Power ||402 |
|RPM ||TQ ||HP ||RPM ||TQ ||HP |
|3,000 ||443 ||253 ||3,000 ||412 ||235 |
|3,100 ||451 ||266 ||3,100 ||416 ||246 |
|3,200 ||456 ||278 ||3,200 ||418 ||255 |
|3,300 ||463 ||291 ||3,300 ||417 ||262 |
|3,400 ||468 ||303 ||3,400 ||421 ||273 |
|3,500 ||470 ||314 ||3,500 ||432 ||288 |
|3,600 ||471 ||323 ||3,600 ||440 ||302 |
|3,700 ||472 ||332 ||3,700 ||444 ||313 |
|3,800 ||470 ||340 ||3,800 ||445 ||322 |
|3,900 ||467 ||347 ||3,900 ||443 ||329 |
|4,000 ||465 ||354 ||4,000 ||443 ||337 |
|4,100 ||464 ||362 ||4,100 ||446 ||348 |
|4,200 ||464 ||371 ||4,200 ||453 ||362 |
|4,300 ||467 ||382 ||4,300 ||460 ||376 |
|4,400 ||469 ||393 ||4,400 ||466 ||391 |
|4,500 ||472 ||405 ||4,500 ||470 ||403 |
|4,600 ||474 ||415 ||4,600 ||473 ||415 |
|4,700 ||474 ||424 ||4,700 ||474 ||424 |
|4,800 ||474 ||433 ||4,800 ||475 ||434 |
|4,900 ||473 ||442 ||4,900 ||475 ||443 |
|5,000 ||473 ||450 ||5,000 ||475 ||452 |
|5,100 ||471 ||457 ||5,100 ||473 ||460 |
|5,200 ||469 ||464 ||5,200 ||472 ||468 |
|5,300 ||466 ||470 ||5,300 ||469 ||473 |
|5,400 ||464 ||477 ||5,400 ||466 ||480 |
|5,500 ||461 ||482 ||5,500 ||462 ||484 |
|5,600 ||455 ||485 ||5,600 ||457 ||487 |
|5,700 ||450 ||488 ||5,700 ||450 ||488 |
|5,800 ||444 ||490 ||5,800 ||444 ||491 |
|5,900 ||437 ||490 ||5,900 ||436 ||490 |
|6,000 ||429 ||490 ||6,000 ||430 ||491 |
|6,100 ||422 ||490 ||6,100 ||424 ||493 |
|6,200 ||413 ||488 ||6,200 ||416 ||491 |
|6,300 ||405 ||486 ||6,300 ||408 ||490 |
|6,400 ||396 ||483 ||6,400 ||400 ||489 |
|6,500 ||388 ||480 ||6,500 ||394 ||487 |
Fel-Pro’s performance head...
Fel-Pro’s performance head gaskets were a perfect match for our 383 build. Our set (PN 1003) featured a 4.166-inch bore and 0.041-inch thickness. They also feature a PermaTorque/blue head gasket body with a solid-steel core to minimize torque loss and blowout. A wire ring combustion chamber seat with stainless steel provides extra sealing force around each combustion chamber.
Before setting down the pair...
Before setting down the pair of Patriot cylinder heads, we threaded in a set of ARP small-block head studs to the block first. They were all treated with a ARP thread sealer since small-block threads enter the water jackets.
We can’t say enough good things...
We can’t say enough good things about these 1.52:1 Ultra Pro Magnum roller rocker lifter arms. We locked all the arms down with the supplied locknuts with a 5/8-inch wrench onto the 7.950-inch intake/exhaust pushrods.
Weiand: Dual- vs. Single-Plane
For our testing, we tried two manifolds on the dyno. Our Weiand Speed Warrior (dual-plane) intake manifold was first. It featured long, separated runners for bottom-end and midrange power, plus a special runner design and larger plenum to flow the air needed from idle all the way up for high-rpm horsepower at 6,000 rpm. The Weiand Team G (single-plane) manifold is designed to build power further up in the rpm, from 2,000 to 8,000 rpm. The single-plane manifold has a raised plenum for increased flow and isolated water passages for improved cooling. Most models feature integral bosses for nitrous oxide.
Using a set of Fel-Pro 1205...
Using a set of Fel-Pro 1205 intake gaskets, we set the dual-plane manifold down and fastened it with a 3/8-inch wrench. For the dyno pulls with the single-plane manifold, we used the same gaskets.
Partially through our runs...
Partially through our runs on the dyno with the dual-plane manifold, we adjusted the jetting on the Holley 870-cfm carburetor. Bob Vrbancic noticed the engine was leaning out toward the top end of the pulls so we added a larger primary (84 jet) and secondary (86 jet) to add more fuel.
Bob Vrbancic kept a vigil...
Bob Vrbancic kept a vigil eye on the timing and adjusted it accordingly. For the dyno pulls with the dual-plane manifold, Bob put 36 degrees of timing and 40 degrees for the single-plane manifold testing. CHP
|THE PARTS BIN |
|MFG ||PN ||ITEM |
|COMP ||818-16 ||Endure-X solid-roller lifters |
|12-000-8 ||Custom grind solid-roller camshaft |
|1604-16 ||Ultra Pro Magnum roller rockers |
|Fel-Pro ||1881 ||One-piece oil pan gasket |
|1003 ||Head gasket set |
|1205 ||Intake gasket set |
|Holley ||0-80870 ||Street avenger 870-cfm carburetor |
|Patriot Performance ||2068 ||Freedom Super Street Series CNC-ported cylinder heads (complete) |
|Pertronix ||60103 ||Flame-Thrower Coil |
|D7100700 ||Flame-Thrower plug ’n’ play distributor |
|Weiand ||8501 ||Street Warrior dual-plane manifold |
|7532 ||Team G single-plane manifold |