Super Chevy
Click here to find out more!

LT1 Engine Build - Late-Model 383 Buildup The Finale

We Got What We Were Looking For-And A Whole Lot More!

Photography by Terry Cole, Roy Landgrave

Seven-hundred horsepower? From a late-model computer-controlled engine? Are you guys crazy? And you want to drive it where? On the street? On pump gas? Good Luck!

We all make goals. It's what carries us on in life. We aim for that bigger paycheck, strive to lose an extra pound or two, or plan for that house in the country with a big yard for the kids to play in (or a garage for us to play in). We would become pretty complacent if we didn't keep reaching for the seemingly unreachable. So when it came to designing the ultimate late-model street powerplant, we had some goals, too. Three to be exact: 700 horsepower, 600 foot-pounds of torque, and a powerband that would enable us to use this potent package on the street-realistically! Did we attain them, you wonder? Keep reading...

To refresh your memory about this project: Our intention when we hooked up with Frank Beck at Beck Racing Engines in Phoenix, Arizona, was to build a late-model LT1 using the best parts available to create a bulletproof, high-power street engine. To begin with, we had a factory block converted to four-bolt mains and had it meticulously machined to accept a set of oversize SRP forged slugs and a stroked Cola steel crankshaft. To be sure that our reciprocating assembly was up to the task of handling 700 ponies, we added a set of Manley H-beam connecting rods, a Titan Sportsman adjustable oil pump housed in an extra-capacity Billet Fabrication aluminum oil pan, Crane valvetrain components, and surefire ARP fasteners throughout.

Once we had assembled the components for a solid short-block, we turned our attention to the induction side of things. First, we chose to use a set of replacement cylinder heads from Airflow Research. The aluminum big-valve (2.05-inch intake, 1.60-inch exhaust) castings have a tremendous flow capacity (both before and after BRE massaged them with a die-grinder) on both the intake and exhaust sides, and they retain the factory's reverse-flow cooling technology. Feeding the "pump" is an Arizona Speed and Marine reworked LT1 EFI direct-port intake manifold that has been Extrude-honed and modified for later use with nitrous oxide injection, and a well-machined billet 58mm throttle body.

Injectors are MSD high-flow, high-pressure units that are fed fuel via a boost-referenced fuel regulator and high-pressure fuel pump from Aeromotive Systems. A Speed-Pro C-Com engine management system from Federal-Mogul makes it all work in harmony (and can be tuned for maximum power using a PC). GM Performance Parts provided the majority of the supporting items, such as fuel rails, a water pump, the Opti-spark ignition system, a timing cover, etc. ATI sent us one of their super Super Dampers, Tilton fired off a small-yet-powerful starter motor, Carbon Components carbon fiber valve covers beautifully hide the roller rockers, and McLeod furnished a nicely machined, heavy-duty flywheel and clutch assembly. To say that this bad boy is going to hook up is most definitely an understatement.

But the biggest part of the equation in our quest for 700 horses is the addition of the D-1 Procharger from Accessible Technologies. The D-1, which is a step up from the company's entry-level P600b unit, flows roughly 25 percent more than it-and also has a higher peak efficiency, the trade-off being the flatness of the boost curve (the D-1 is peakier). Typically, the engineers at Procharger don't recommend using the P600b on anything making much more than 650 hp (max), whereas the D-1 works nicely up to and above 850 ponies, which was perfect for this project.

Machining and long-block assembly were done at BRE's Phoenix shop, while all of the peripheral add-ons were installed by your dedicated staff at Super Chevy. Once the basic engine was together, we put it in the bed of a small truck and headed toward Vrbancic Brothers Racing and their state-of-the-art DTS dyno facility to see where we stood on the horsepower curve.

In the previous three parts to this story, we've focused on making sure the sum of all of the trick parts added up to one cool late-model stroker engine. While we're sure that all of the trick parts went together flawlessly, there's only one thing that really matters, and that's how she does on the dyno.

Making The Numbers!
Making an electronic, fuel-injected small-block spin the dyno needles into the upper horsepower and torque stratosphere is no small feat, to say the least. To do so required the special talents of both man and machine. To manage the 383's fuel and spark delivery, we employed the aforementioned C-Com engine computer. To manage the C-Com, we got help from one of the country's premier electronic tuners, Craig Railsback of BDS Blowers. Craig joined us with his laptop PC for two sessions and had our modern LT1 running virtually right on target with little effort.

Our goal on the dyno was to learn three things: How much power and torque will the engine make normally aspirated on pump gas; how much with the D-1 Procharger on 92 octane; and, for bragging rights, how much power we can make with the D-1 on racing fuel.

After meeting all three parameters, the first conclusion we made was that this combination of parts was perfect for a street engine. Despite the high-flow cylinder heads, our 383 stroker did not make any additional power after 6,000 rpm (probably due to the limited flow capacity of the stock-style LT1 intake). Essentially, on all three trials, the mighty mouse was screaming that its power was done at six-grand! But, as a tribute to how well matched this combination was, the power and torque curves were excellent, with peak numbers in all tests within a couple of hundred rpm of one another. And, with boost, the torque came on immediately and never fell off, all the way to redline.

So, you're probably wondering at this point what those magic numbers are. What was our goal originally? First, it was to make 700 ponies on good gas. Second, we wanted enough torque to get our not-so-lightweight '96 Camaro convertible up and running-in a hurry. With 110-octane racing fuel, our 383 hit unbelievable numbers of 735 horsepower and 693 foot-pounds of torque! And as far as those numbers being in a usable rpm range, power peaked at 5,600 rpm, while the top torque mark wasn't too far behind at 5,500 rpm. The torque curve was more like a table top on the graph, though, as the engine made more than 500 foot-pounds at 3,000 rpm and never dropped below 680 through shutoff.

We know what you're thinking at this point. With high-octane fuel, we got aggressive with the ignition timing. Not so! In fact, the timing was ultra conservative, according to Craig, at around 36 degrees, while maximum boost was just a hair over 10 psi. Everything worked perfectly during this session, which led us to come back and run the engine on pump gas both off boost and with the blower belt on.

With Unocal 92-octane premium unleaded being pushed through the Aeromotive Systems electric pump at a maximum of 65 psi, we ran a baseline test of the engine without running the blower, just to see how stout this 383 was. Now, considering that the compression of this engine was down to around 9.4:1 to allow for the additional boost, and add in the fact that the 72-pound injectors were designed more for a supercharged application, we weren't sure just what kind of numbers to expect. What we got was a pretty stout non-blown engine, with a maximum of 422 horses (5,600 rpm) and 420 ft-lbs of torque (5,000 rpm). This was with 42 degrees of total timing and a running temperature of 212 degrees F.

Doing the math at this stage tells us that we gained a whopping 313 horsepower and 273 foot-pounds of torque with good gas and 10 pounds of boost! Simply incredible.

RACING GAS
RPM TORQUE HP
3,500 543 363.9
3,600 564 386.6
3,700 571 401.3
3,800 584 422.7
3,900 597 443
4,000 607 461.7
4,100 618 481.8
4,200 631 506
4,300 640 523
4,400 647 542
4,500 656 561
4,600 666 584
4,700 673 600
4,800 680 623
4,900 683 636
5,000 687 655
5,100 689 668
5,200 690 683
5,300 693 700
5,400 693 712
5,500 693 726
5,600 690 735
5,700 677 735
5,800 647 715
5,900 618 694
6,000 598 681

But what about the real test? Pump gas on boost. Well, we were not disappointed, especially since we had to back the timing way down from what it was with the high-octane fuel (from 36 degrees to 28). Despite the loss of timing, the difference in horsepower and torque readings between good gas and pump gas measured only a slight loss of 6.6 percent in horsepower and a minute 3.2 percent drop in torque. That meant that our street-worthy 383 stroker has a legitimate 686 ponies and 671 ft-lbs of torque on tap, on drive-through 92-octane junk fuel.

As for drivability, the peak horse reading was at 5,700, which is where the dyno stopped the test (yup, it was still climbing), while torque peaked at a tractor-like 4,900rpm. This engine, with a maximum of 9.7 pounds of boost, made 504 ft-lbs of torque at 3,100 and was still making 634 ft-lbs at 5,700 when we shut her down. And, the temperature needle never got hotter than 212 degrees F (which is about normal for late-model reverse-cooling LT1s).

In summary, this engine may have more horsepower than most of us will ever be able to use on the street. But, for the cost of good parts and the ATI D-1 Procharger, you can have a bona fide 700-horse street engine that is tame enough to sit in traffic or wild enough to propel its nearly two-ton carriage down the quarter-mile in the 10-second zone. That part of our project still remains to be seen. But stay tuned-in the coming months we will attempt to swap out our donor car's original low-mileage LT1 and stab in this potent 383 stroker in its place.

Hot Box
I'm a hot rodder to the core, but as most of you know, my roots are in high-winding small-blocks with carburetors and solid-lifter roller cams, not electronics and fuel injection. I don't profess to know a lot about the computer controllers that can wring out the most power from today's EFI machines. Sequential port fuel injection; bank-to-bank firing, individual cylinder timing. It all sounds like space-age jargon to me. But with the help of BDS's Craig Railsback and the Federal-Mogul Speed-Pro C-Com electronic engine management control system, I'm learning.

First, the C-Com software is designed for those wishing to have the most control over their EFI machines. It's designed for competition, not to circumvent the factory OBD-11 computer for street use. The C-Com allows the engine tuner to choose what sort of fuel-injection control best suits the conditions. Two systems are available.

First, for most applications, the Bank-To-Bank system is perfect. This controller fires half of the engine's injectors each 180 degrees of crankshaft rotation. This gives the engine improved fuel delivery and performance, and, for street applications, better driveability. This system is ideal for converting an engine from a carburetor to EFI. Other items that this system can control are the idle air, fan, fuel pump, single-stage nitrous, and program knock retard. A wide-band O2 sensor for closed-loop can also be used. And, it can be upgraded to the Sequential system, if the need arises.

The Sequential Electronic Fuel Injection system was designed for the ultimate in power production and tuning. It uses technology that will individually fire each injector for optimizing fuel delivery. It can also be equipped with options that allow for individual cylinder fuel/timing, and will facilitate adding a two-stage nitrous setup.

Both systems can be individually programmed by using a PC-based (386 and higher) laptop computer. With this capacity, you can literally program the engine to recognize the special needs of specific cams, superchargers, compression ratios, etc.

In our case, we were able to tell the engine that it needed to have driveability as well as maximum power output. And, when the 383 finds its way into the Camaro's engine bay, if the need arises to add a little more fuel or back the timing off, our PC won't be too far away.

PUMP GAS
RPM TORQUE HP
3,000 490.8 283.3
3,100 504 298.5
3,200 511 311.2
3,300 521 328.1
3,400 530 342.6
3,500 540 360.5
3,600 548 375.2
3,700 556 391.7
3,800 568 411.2
3,900 581 432.3
4,000 591 449
4,100 603 471.9
4,200 616 492.7
4,300 624 511
4,400 632 529
4,500 647 554
4,600 659 578
4,700 666 595
4,800 669 611
4,900 671 625
5,000 670 638
5,100 670 651
5,200 668 660
5,300 665 672
5,400 658 676
5,500 651 682
5,600 643 685
5,700 634 686
SOURCES
Aeromotive Systems
218 W. 74th St.
Kansas City
MO  64114
Extrude Hone
1 Industry Blvd.
Irwin
PA  15642
8-00/-613-1065
www.extrudehone.com
Airflow Research
28611 W. Industry Dr.
Valencia
CA  91355
Federal Mogul/Fel-Pro
26555 Northwestern Hwy.
Southfield
MI  48034
Arizona Speed and Marine
6313 W. Commonwealth
Chandler
AZ  85226
GM Performance Parts
www.gmperformanceparts.com
ARP
531 Spectrum Circle
Oxnard
CA  93030
805-278-7223
Manley
1960 Swarthmore Ave.
Lakewood
NJ  08701
7-32/-905-3366
www.manleyperformance .com
ATI ProCharger
14801 W. 114th Terr.
Lenexa
KS  66215
913-338-2886
www.procharger.com
McLeod
1600 Sierra Madre Cir.
Placentia
CA  92870
Beck Racing Engines
21616 N. Central Ave., Suite 1
Phoenix
AZ  85024
MSD
El Paso
TX  79936
915-857-5200
www.msdignition.com
Billet Fabrication
649-F Easy Street, Dept MMFF
Simi Valley
CA  93065
Pro Gram Engineering
P.O. Box 472
Barberton
OH  44203
Carbon Components
223 17th St.
Huntington Beach
CA  92548
SRP
714-898-9764
www.srp.com
CNC Cylinder Heads
727-527-8866
www.cncheads.com
Tilton Engineering
P.O. Box 1787
25 Easy St.
Buellton
CA  93427
Childs & Albert
24849 Anza Drive
Valencia
CA  91355
www.childs-albert.com
Titan
13001 Tree Ranch Rd.
Ojai
CA  93023
Cloyes
P.O. Box 287
Paris
AR  72855
Tpis
4255 County Rd. 10 East
Chaska
MN  55318
Cola Performance Products
19122 S. Santa Fe Ave.
Rancho Dominguez
CA  90021
Vrbancic Bros. Racing
N/A
customcarbs.com
Crane Cams
530 Fentress Blvd.
Daytona Beach
FL  32114
3-86/-252-1151
N/A
www.cranecams.com
  • «
  • |
  • 1
  • |
  • 2
  • |
  • 3
  • |
  • View Full Article
Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
Super Chevy