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383 Chevy Small Block LS1 Engine Build - LS Resurrection
Building A Carbureted 383 Gen III Stroker With Turn Key Engine Supply
Dec 1, 2008
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383 Chevy Small Block LS1 Engine Build - LS Resurrection
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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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, 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.
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