World also manufactures the...
World also manufactures the LS1X cylinder heads used on our engine. They use 1.437-inch-diameter dual springs with a 125-pound seat pressure.
Although World was not yet offering Warhawk crate engines at the time of our buildup, the company was offering a variety of short-block assemblies and partial engines, the most popular being a 481-inch combination that uses the tall-deck block. For our project, we started with World's 427-inch short-block with LS1X heads, PN 103251A. It uses a standard-deck block (9.240 inches) and 4.125-inch bores. With a 4.000-inch stroke, it gives our engine the classic big-block displacement of 427 ci. It also is filled with forged reciprocating parts.
And because World's short-block doesn't include a camshaft, we looked to GM for an off-the-shelf LS7 bumpstick, PN 12571251. It has a lot of lift, and we figured that any cam good enough for the Z06 ought to do just fine for our street-based project.
A slew of carbureted intake systems have been developed for the LS engine, and they work great with the Warhawk. We used a high-rise, single-plane manifold and an 870-cfm Dominator-type four-barrel carb. It sounds like a lot for the street, but World Products insists the combination is docile enough for traffic duty.
Because the Warhawk block is based on the LS engine, it is designed to accommodate production-style accessories and components, including the oil and water pumps, the front cover, the various sensors to trigger the ignition and adjust timing, the ignition coils, the front-end dress kit, and the oil pan. We used a mixture of GM and aftermarket parts, including a complete MSD ignition system and controller kit.
The LS1X heads also use Manley...
The LS1X heads also use Manley 2.080-inch intake valves, 1.600-inch exhaust valves, and 64cc or 72cc combustion chambers. Ours used the 72cc version to keep compression in check.
The Warhawk accommodates the Z06-type dry-sump oiling system, so builders can use either the low-profile factory LS7 pan and a remote oil reservoir or a conventional wet-sump pan. The inlet/outlet ports for the dry-sump pan will interfere with some crossmembers, so unless you really want the exoticness of the dry system, stick with a conventional pan like the GM F-car unit. The Corvette LS pan has wings for high-load cornering, but on a street/strip car, the wings only interfere with the chassis.
Building a Warhawk-based engine is just like building a GM LS engine. In fact, our World Products project engine used a number of GM accessories to round out the assembly. Some of the fasteners are torque-to-yield types, meaning the final torque specs are reached with a torque-angle meter or similar tool.
And while the LS-type engine is different than a conventional carbureted mill with a distributor, getting it up and running is surprisingly easy and straightforward.
Here are the basics of what you need:
* Ignition system - GM or aftermarket (such as MSD), including coil packs, plug wires, and spark plugs
* Crankshaft-position, camshaft-position, and other sensors
* Ignition controller
Large, straight-flowing 235cc...
Large, straight-flowing 235cc intake runners have a "cathedral" shape, similar to GM's LS1 head. World's LS7X heads offer another 50 cc's of intake runner volume; higher-flowing, CNC-ported versions are also on the way.
With the MSD ignition kit, wiring the engine and getting it running was a snap. The valve-cover-mounted ignition coils connect to the wiring harness with only a single connection per side. The harness also plugs into the crank- and cam-position sensors, as well as a few others, and that's about it. When everything is plugged in and the engine is started for the first time, the ignition control automatically sets the timing--no timing light required.
By the way, one of the best guides to setting up an LS engine in an older vehicle is available from GM Performance Parts. It's called LS1 Engine Kit Installation Guide, and it carries PN 88959384. While the title says "LS1," the content is applicable to any LS-based engine swap.
An internally balanced Eagle...
An internally balanced Eagle 4340 forged-steel crankshaft was used to deliver a 4.00-inch stroke. A crankshaft with a longer snout is required when adapting the factory LS7's dry-sump oiling system. Our project used a conventional wet-sump system.
A critical component for all...
A critical component for all LS engines is the toothed crankshaft sprocket, which is what the crankshaft-position sensor reads to ensure accurate ignition timing. LS1 engines use a 24-tooth sprocket, while later engines, such as the LS7, use a 58-tooth wheel.
Our buildup started in earnest...
Our buildup started in earnest with the crank being lowered into the deep-skirt Warhawk block. It was then clamped in place with the billet main caps.