383 Chevy Small Block LS1 Engine Build - LS Resurrection
Building A Carbureted 383 Gen III Stroker With Turn Key Engine Supply
From the December, 2008 issue of Chevy High Performance
By John Nelson
Photography by John Nelson
As the old saying goes, "The end of one man's garage space is the start of another man's project." OK, we made that up. Nevertheless, it's true for so many of us-we tenaciously hang onto parts or engines or even entire cars, certain that sometime in the future we'll actually make something of our cache of go-fast goodies. Often, however, that future happens for the next guy-the one who gets a smokin' deal when all that stuff just finally has to go. In this case, the treasure to be had was a complete LS1 engine with a spun bearing, minus coil packs, available for a ridiculously low $250 when the previous owner just had to get it out of his garage. You can be sure we'll be putting this bargain find to good use, starting with its re-creation by Turn Key Engine Supply into a stout-and carbureted-383 stroker.
The decision to add some capacity to this LS1 ended up being something of a no-brainer. The motor had to come apart, and the damage caused by the spun bearing was severe enough to require a new crankshaft. Therefore it made sense to increase the stroke and add some displacement to our Gen III creation. In fact, this is really the only practical way to gain more cubes with the aluminum LS1 block, since bore increases are limited with the factory pressed-in cast-iron liners. A very minimal overbore-0.005 inch to 3.905 inches-along with an increase in stroke from 3.62 to 4.00 inches, yielded that magic Chevy stroker number: 383 ci.
As for component choice in the lower end, we plan to lean on this thing pretty hard, so we wanted to create a bulletproof short-block. The factory six-bolt main configuration is a more-than-solid foundation. Once it was filled it with a 4340 forged-steel Lunati crank and 4340 rods (6.125 inches long, a hair longer than the factory 6.098 pieces) along with JE Forged Side Relief (FSR) pistons that brought us in at a pump-gas-friendly 10.3:1 compression ratio, we knew we'd devised a bottom end that could handle anything we threw at it. And by "anything," we mean forced induction. But that's another story.
When it came to our heads and cam combo, we were primarily focused on making high-rpm horsepower, hopefully without totally sacrificing lower-end grunt. We went for the bottom-of-the-page choice and picked out a Comp Cams XER287HR. It's a big cam for an LS motor. According to Comp's Billy Godbold, the engine's basic architecture incorporates a very stiff valvetrain (thanks in part to the cam's 55mm core size). What does this all mean? The lobes are quicker, for one, getting the valves open further, faster. It also means that less duration is lost to valvetrain deflection, so they stay open longer. In short, the engine gets every bit of lift and duration promised on the cam card.
We teamed the big 'stick with AFR's 205cc LS1 Mongoose heads, which enabled us to kill two birds with one stone. On the one hand, these heads flow extremely well and are designed to accommodate LS1, LS2, or LS6 powerplants displacing as much as 408 ci, so they lend themselves to the high-rpm power we were seeking. On the other hand, the 205cc intake openings are designed to maintain high port velocity, which helps out with bottom-end power. "At low speeds, smaller ports do a better job of filling the cylinders," says AFR's Tony Mamo. "They really shine in the real world, making the engine more responsive at in everyday, part-throttle situations. These types of gains are rarely measured on a dyno, as most testing is done at WOT."
1. We topped our Victor Jr. LS1 manifold with a Holley 750 Street HP carb; best power numbers were obtained with a Wilson Manifolds 1-inch tapered combo spacer in place.
2. MSD's 6LS ignition controller is a real plug-and-play deal. You can use preprogrammed timing curve modules or program it with a laptop if desired.
3. MSD coil packs and Super Conductor wires provide higher-energy sparks for hi-po setups.
4. AFR 205cc LS1 Mongoose cylinder heads flow big numbers with high port velocity-the Holy Grail of head design.
5. This bargain-find Gen III block is filled with bulletproof internals from Lunati, JE, and Comp.
6. Need a little bling on your LS? The chrome balancer and bolt from Turn Key runs $225.
7. QTP makes this trick two-piece timing cover, allowing cam changes without disturbing the crank pulley.
Although most of Turn Key's Gen X engines are fuel injected-and we intend to try out EFI on this particular engine-we decided to go carbureted for this project. "We'll cater," said Turn Key's Kory Enger, so we bolted up an Edelbrock Victor Jr. LS1 manifold and teamed it with an MSD 6LS ignition controller. While we were looking to save a few bucks compared to the cost of an EFI system, the setup we used had one big advantage: simplicity. And sure, we're saying that installing the manifold, slapping on a carb, and dialing it in was simple. But the same thing goes for the MSD ignition controller-it truly is plug-and-play, especially if you go with one of the preprogrammed timing curve modules. How simple was it? This writer actually hooked most of the harness up, minus the power and ground wires. With that done, all that was left was to fire her up and have at it.
When all was said and done, it was hard to be disappointed with the results: 560 hp at 6,500 rpm, along with 505 lb-ft of torque at 5,100 rpm. And despite our emphasis on the upper end, we still managed a pretty broad torque band, maintaining 400-plus lb-ft from 3,300 rpm all the way to the end of the run at 7,000. They're good numbers, especially when you consider that we're dealing with only 383 ci and 10.3:1 compression. There's more in store for this thrown-away LS, but we're off to a good start. Check it out.
What we did
Turned a cast-off LS1 into a potent stroker motor
We got big-block horsepower numbers from an aluminum small-block
Turn Key Engine Supply began...
Turn Key Engine Supply began this project by totally disassembling, cleaning, and machining our LS1 core. Engine builder Terry Clason pointed out that only a minimum of clearancing was needed to accommodate the compact Lunati rods.
Clason began by installing...
Clason began by installing the cam bearings. It's imperative that the oil holes be properly positioned; they should be at approximately 3 and 9 o'clock. The cam was then coated with assembly lube and slid into place.
After installing the upper...
After installing the upper half of the Clevite H-Series bearings we used for this build, Clason set our beyond-stout Lunati Pro-Series 4340 forged crank into place. Note that the crank comes with an LS1/LS6-style 24-tooth crank trigger, aka reluctor wheel, preinstalled. LS2/LS7 mills use a 58-tooth crank trigger and require a different ignition controller.
One of the biggest advantages...
One of the biggest advantages of a Gen X powerplant is the deep-skirted block design. The six-bolt main caps that fit into it make for an extremely strong lower end. The four main bolts get torqued to 58 ft-lb, while the side, or cross-bolts, get 20 ft-lb.
The standard Gen III oil pump...
The standard Gen III oil pump is more than up to the task of oiling our 383 LS, so that's what we used. On the other hand, we upgraded our timing set with one of Turn Key's double-roller setups. Note the oil galley plug Clason is pointing at; failure to install this small but critical piece would lead to a noticeable lack of oil pressure at startup.
Our reciprocating assembly...
Our reciprocating assembly consisted of a Lunati rod/JE Pistons tandem. The 6.125-inch 4340 rods are lightweight and compact in size, requiring minimal block clearancing as noted before. JE's Forged Side Relief (FSR) pistons are designed to avoid reluctor wheel clearance issues in Gen X engines. The inverted-dome configuration is intended to create forced-induction-friendly compression ratios.
Lower-end assembly continued...
Lower-end assembly continued with a factory windage tray and oil pickup. It's important to check for windage tray clearance when assembling a Gen III stroker setup. Clason simply set the tray in place and rotated the motor. Noting that the crank hit the tray, he shimmed it up at each mounting point with a pair of washers.
Cam changes are already very...
Cam changes are already very easy on LS motors since you don't have to remove the lifters. We made sure future swaps would be extra easy to accomplish by installing one of QTP's LS1 Quick Cam Change timing covers. With this setup, you can get at the cam without removing the crank pulley-something we'll appreciate even more when this powerplant is actually in an engine bay.
Working his way up, Clason...
Working his way up, Clason filled the factory lifter trays with Comp High Energy rollers to accommodate our intended high-rpm antics. What else can we say? You put the lifters in the trays, put the trays in the engine, and bolt the trays into place. For all the great design features of the Gen X engine family, we dig details like this.
Our lungs of choice were AFR's...
Our lungs of choice were AFR's LS1 Mongoose Street Aluminum Heads. They're fully CNC'd and come with 66cc combustion chambers. Although they produce sizeable flow numbers, the 205cc ports are meant to promote high air velocity and better cylinder filling, leading to good low-end torque and crisp throttle response. We ordered ours with the PN 8019 spring upgrade, which is recommended when running more than 0.600 inch of valve lift and exceeding 6,600 rpm. And a word to all you Corvette and Camaro owners out there: These babies are smog-legal.
We've talked about the inherent...
We've talked about the inherent valvetrain stiffness of the Gen X design. We decided to up the ante by installing a Yella Terra shaft-mount roller rocker arm setup. AFR's Mamo, who clued us in on this deal, has seen power increases of as much as 5 rwhp due to reduced friction and less flexing of the rocker body, which equals improved action at the valve for more airflow. More importantly, he says, these rockers "have a much smaller wipe pattern on the tips of the valves and offer better valvetrain geometry. This reduces sideloading of the valve stem and reduces valve guide wear considerably. With beefy springs and aftermarket cams approaching or exceeding 0.600 lift, the stock rocker arms can ruin a set of bronze guides in less than 20,000 miles."
We finished up our day at...
We finished up our day at Turn Key by bolting on our Edelbrock Victor Jr. LS1 intake-we're sure you already know that the Gen X O-ring gasket design (no sealant!) makes this extremely easy. If you look closely you can see one of the two knock sensors in the valley pan, denoting that this as a Gen III block. (Gen IVs, as in LS2s and LS7s, have the sensors on the side of the block.)
We prepped for our test session...
We prepped for our test session at Westech Performance by installing the MSD coil packs, plug wires, and ignition controller. The controller box comes with a complete wiring harness and box mounting bracket, but you'll need a coil mounting bracket to attach the MSD pieces.
You've got two choices when...
You've got two choices when it comes to picking an LS1/LS6 Ignition Controller, depending on what options you're looking for. The Victor Jr. LS1 intake can be ordered with or without this MSD-built controller. This one's about as easy as it gets. You hook up all the wires, plug in a timing control module based on Edelbrock's application chart, and fire it up. You can do the same thing with the 6LS, or you can plug in a laptop and use MSD's Pro-Data+ software to program several variables, including timing curves.
How easy are these ignition...
How easy are these ignition controllers to hook up? All the wires are marked, so you just have to plug them in as indicated-here you can see the MAP sensor (1), which also requires a vacuum source, and the cam sensor (2). After that, you just hook up a power source and ground, and you're good to go. Well, almost. The MSD 6LS setup comes with a harness for a step retard and a two-step rev limit built in (3). If the harness isn't hooked up, there's a default 5,500-rpm rev limit to be dealt with.
Our man Steve Brul plugged...
Our man Steve Brul plugged in with a laptop and dealt with that pesky rev-limiter issue, then we made several pulls with the preprogrammed timing modules. He then used the Pro-Data+ software to experiment with different timing options. We made our peak power number of 560 hp with 32 degrees total timing, about 4 ponies more than with the best timing module. Making timing changes is just scratching the surface of what this software can do-you can bet at the very least that we'll be making use of the boost retard feature in the future.
It's just your common, everyday,...
It's just your common, everyday, 560hp, carbureted 383 small-block, right? We know, not exactly, but it's hard to argue with success, and this thing makes the numbers. We think it's a nice melding of new and old technology-not to mention that it looks pretty cool, too. You can bet we'll be pushing it further in the months to come.
|CAMSHAFT SPECS |
|Manufacturer ||Comp Cams |
|PN ||54-448-11 |
|Grind Number ||XER287HR |
|Type ||Hydraulic roller |
|Valve lift ||0.605/0.609-inch |
| ||intake/exhaust |
|Duration at 0.050 ||238/240 |
| ||intake/exhaust |
|Lobe separation ||112 |
|FLOW FIGURES |
|LIFT ||INTAKE ||EXHAUST |
|0.200 ||140 ||112 |
|0.300 ||200 ||170 |
|0.400 ||251 ||203 |
|0.500 ||281 ||221 |
|0.550 ||292 ||226 |
|0.600 ||298 ||230 |
|CFM at 28 inches H2O |
|PRICE LIST |
|MANUFACTURER ||PN ||DESCRIPTION ||PRICE |
|AFR ||1510 ||205cc LS1 Mongoose heads || |
| || ||w/ spring upgrade ||$2,465 |
|ARP ||134-3609 ||Head bolt kit ||150 |
|Comp Cams ||54-448-11 ||XER287HR ||400 |
| ||7955-16 ||Hi-Tech pushrods ||135 |
| ||850-16 ||High Energy lifters ||189 |
|Edelbrock ||29087 ||Victor Jr. LS1 manifold ||290 |
| ||or 2908 ||Victor Jr. LS1 manifold w/ module ||690 |
|JE Pistons ||264041 ||F.S.R. Pistons ||737 |
|Lunati ||JO711ER ||Pro Series crankshaft ||1,651 |
| ||6125FM3 ||4340 I-Beam Rod Set ||1,460 |
|MSD Ignition ||82458 ||LS1/LS6 Blaster coil packs ||632 |
| ||32079 ||8.5mm Super Conductor wire set ||102 |
| ||6010 ||6LS Ignition Controller ||313 |
|Quick Time Performance ||QCC-LS1 ||Gen III Quick Cam Cover ||425 |
|Turn Key Engine Supply ||872012 ||Chrome balancer w/ bolt ||225 |
|(including machine work) ||7145 ||Double-roller timing chain ||175 |
| ||12498544 ||Head gaskets (set) ||50 |
| ||Balancing ||200 |
| ||Cylinder boring ||250 |
| ||Assembly on used motor ||2,000 |
|Yella Terra ||YT6645 ||Shaft-mount rocker arms ||445 |
| || ||Total ||$12,294 |
|Options || ||New LS1 block ||800-1,000 |
| || ||New motor assembly ||1,500 |
|DYNO DATA |
|RPM ||LB-FT ||HP |
|2,600 ||369 ||182 |
|2,700 ||372 ||191 |
|2,800 ||370 ||197 |
|2,900 ||368 ||203 |
|3,000 ||369 ||211 |
|3,100 ||374 ||221 |
|3,200 ||385 ||235 |
|3,300 ||404 ||254 |
|3,400 ||416 ||269 |
|3,500 ||424 ||283 |
|3,600 ||427 ||293 |
|3,700 ||433 ||305 |
|3,800 ||441 ||319 |
|3,900 ||448 ||332 |
|4,000 ||456 ||347 |
|4,100 ||459 ||358 |
|4,200 ||461 ||369 |
|4,300 ||465 ||381 |
|4,400 ||474 ||397 |
|4,500 ||480 ||411 |
|4,600 ||487 ||426 |
|4,700 ||491 ||440 |
|4,800 ||498 ||455 |
|4,900 ||501 ||468 |
|5,000 ||503 ||479 |
|5,100 ||505 ||490 |
|5,200 ||505 ||499 |
|5,300 ||502 ||507 |
|5,400 ||499 ||513 |
|5,500 ||497 ||521 |
|5,600 ||497 ||530 |
|5,700 ||496 ||539 |
|5,800 ||494 ||545 |
|5,900 ||487 ||547 |
|6,000 ||483 ||552 |
|6,100 ||476 ||553 |
|6,200 ||469 ||554 |
|6,300 ||464 ||556 |
|6,400 ||457 ||556 |
|6,500 ||453 ||560 |
|6,600 ||443 ||557 |
|6,700 ||438 ||558 |
|6,800 ||428 ||554 |
|6,900 ||418 ||549 |
|7,000 ||407 ||542 |
|DYNO DETAILS |
|Headers ||1 3/4 Kooks long tubes w/ 18-inch extensions |
|Advance ||32 degrees |
|Fuel ||91-octane unleaded |
|Carb ||750-cfm Street HP |
|Jets ||73 primary/75 secondary |
|Max torque @ rpm ||505 @ 5,100 |
|Max power @ rpm ||560 @ 6,500 |
|Average torque ||449 |
|Average power ||413 |
|Build Sheet |
Specifications not listed are the same as stock. Except as noted, all dimensions are in inches.
|Displacement ||383 ci |
|Bore x Stroke ||3.905 x 4.000 |
|Compression ||10.3:1 |
|Rod center to center ||6.125 |
|Piston deck height ||0.00 |
|Chamber volume ||66 cc |
|Rod bearing clearance ||0.0025 |
|Crank endplay ||0.003 |
|Piston ring endgap ||1.5mm top, 1.5mm second |
|Main bearing cap torque ||58 ft-lbs |
|Main bearing/cross-bolt ||20 ft-lbs |
|Rod bolt torque ||85 ft-lbs |
|Head bolt torque ||75 ft-lbs |
|Air Flow Research|
|Autotronic Controls Corp. (MSD Ignition)|
|Holley Performance Products|
|Quick Time Performance|
|Rockett Brand Fuel|
|Turn Key Engine Supply|
|Westech Performance Group|