How we built a reliable 1000hp street engine from a junkyard reject
If you've seen THIS VIDEO on my '64 Pontiac Bonneville build you'll have seen me talk about the supercharged engine under its big green bonnet. If you want to see how it came together, read on...
The internet is awash with stories of "1000hp" cars, which is awesome! But there is actually a huge difference between a "junkyard" 1000hp build (which is generally only good for a few pulls on a dyno or down a drag strip) and something engineered from the ground-up to make that kind of power.
We tagged along to pester Troy Worsley from Warspeed Industries as he took a sad, dirty LS and turned it into a monster street car engine ready to make four-digit power figures... and heaps maaaad V8 noises.
This is how the engine started off, freshly imported from the USA. There are over 40 different engines in the LS family, which spans Gen III and Gen IV engines, and they range from 4.8-litres up to 7-litres, and are made in alloy or iron-block variants. Australia never got iron-block LS engines in factory-fitted cars, so we have to bring them in second-hand if we want to build a tough, factory-based motor.
This engine is a Gen III iron-block 6-litre (364ci), coded LQ4, and was found in General Motors SUVs and large vehicles from 1999-2007. These are super-popular for big-horsepower builds thanks to the strength of the iron block and its ability to have deep-breathing LS3-style cylinder heads fitted to it. For this build only the bare block will be retained, sorry Sloppy Mechanics.
As you can see, this engine led a fairly hard life towards its end. Here, you can see the "cathedral port" style Gen III cylinder heads, which feature a triangulated-style top to the intake port. The Gen IV "rectangle port" heads are a larger rectangle shape, while LS7 heads feature monster "square port" heads that are a whole new world of awesome airflow, but don't fit regular LS intakes.
Some people reckon these LQ4 engines only need a set of good cylinder heads, a spicy camshaft and some basic maintenance to make 1500hp (once you strap a big ol' spooly boy to your exhaust manifolds), but these are production motors that have variable build quality so this motor is getting properly machined and all-new internals so it can reliably make Bugatti Veyron-levels of power.
Troy Worsley, the ring-gapping scientist behind Warspeed Industries, plays with all sorts of engines but is an LS specialist.
Once the block was fully machined (check out other story HERE) by Jenkins Performance Engines Troy fitted ARP main studs to the block to keep the bottom-end from twisting (also known as "walking") under stress. Troy says he normally spends around four hours cleaning the bare blocks before they are ready to be built, starting with main studs and fresh cam bearings.
The basis of this engine is a Texas Speed stroker kit that I specced out with them to be a snappy motor on pump fuel or E85. Texas Speed sent a forged crankshaft and con rods, and special forged Wiseco pistons which equal 10.67:1 compression ratio. A custom-grind Texas Speed hydraulic roller camshaft (a 233/245 @0.50", with a 116 LSA for a minor chop rating) and Johnson tie-bar lifters.
Measuring everything is critical to any engine build, and Troy has gone right through all the parts to measure clearances and triple-check against the manufacturer specifications. This prevents assembling the motor only to discover parts rubbing or geometry problems or, worse, having a failure once the engine is in the car and running hard.
The bearings need clearance to keep everything oiled, and Troy checks the bearings in every cap once it is torqued down to ensure both halves of the bearing shell is right. If the clearances around the bearings aren't correct this can lead to epic destruction that will see your entire motor thrown in the bin.
Marty heard there was a party going on with precision measuring tools and so he couldn't stay away. Here he torques down the crankshaft in the block, before he ran off shouting something about cheap kebabs.
The con rods and pistons have been balanced and trial-assembled several times before Troy gets to setting the ring gaps. He checks the shape and dimensions of each cylinders so he knows he can set the ring gaps on one cylinder and they'll match across the other seven. There is no short-cutting this step and Troy mentioned several times how much it brought him nothing but sweet floral joy to do this step.
The pistons and con rods are then knocked into each cylinder and torqued-down.
The camshaft is fitted, and then the lifters, before an Aussie Rollmaster double-row timing chain is installed. Rounding out Day 1 of the build had Troy fit a Mellings oil pump to the front of the block, which will ensure the crushed dinosaurs always get to the right spots in the engine.
Troy checks how far above the deck height the pistons sit at Top Dead Centre, just to ensure the slugs and valves don't have a fight and wreck your party. If they kiss, the destruction is epic inside your engine, so Troy uses plastigauge on one cylinder (which has the head torqued down and a rocker and pushrod fitted) to triple check everything clears.
By the time we got back to Troy's shop a couple of days later he'd already fitted the Gen IV timing case (which comes with a front-mounted cam sensor), water pump, one of his timing pointers, the aftermarket gated sump (oil pan), balancer and front pulley, and was test-fitting the Precision Racing Components cylinder heads (supplied by Texas Speed) over the ARP 2000-grade head studs.
The PRC heads are rectangle-port LS3-style CNC-ported units which should flow huge numbers once compressed air is jammed into them. While factory heads use four bolts per-cylinder to bolt them down many aftermarket or high-end cylinder heads use six bolts per-cylinder to offers much better clamping when big boost is involved.
Because this was a full custom engine set-up Troy needed to measure this specific engine for pushrod length, and it just so happened it needed custom-length units from Manton in the USA. Valvetrain geometry is all-important for pushrod engines as incorrect pushrod length or lifter-preload can stop engines from running as pushrods that are too long will hold intake and exhaust valves open.
This is the view compressed air is going to see as it hits the Harrop Engineering water-to-air intercooler. For over 60 years Harrop Engineering has been building awesome high-end parts and their supercharger kits are some of the best quality parts I've seen in my 20 years working in the industry.
The power-adder is one of Harrop's epic TVS2650 units, featuring a new and seriously huge Harrop 110mm drive-by-wire throttle body. The Harrop superchargers, available in a range of sizes and as complete kits or blower units on their own, use the Eaton TVS-style twin-vortices rotor pack for an efficient way to feed compressed air into a given engine. The kit being fitted to the Warspeed engine included the intake manifold, fuel rails, water-to-air intercooler, and 8-rib belt and tensioner set-up.
Photo: Matthew Everingham, courtesy Street Machine
All up this 6.6-litre engine should make around 1000hp at the crank on pump unleaded fuel, which is great considering it uses almost all off-the-shelf parts. Some decry this dinosaur-burning, pushrod V8 as an outdated boat anchor but this comes down to personal taste - some people like jazz and others like techno.
If you want to read more about this engine you can see a story I wrote for Street Machine on it, HERE.