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LS Fun for Cheap! Budget Rebuild LQ4 Makes 464 hp!

Junkyard Attack Dog: 464 hp from a salvaged and rebuilt LQ4 truck engine

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Unless you’ve been living under a rock, you’ve no doubt been regaled with the benefits of Chevrolet’s LS-based engines. To be honest, all the hype is entirely justified. They are simply better in every way compared to the Gen I small-blocks that came equipped in our Chevys. Well, in every way but one: cost. Yep, getting an LS engine in your car is no inexpensive endeavor. For a typical LS crate engine you can easily spend $7,000 and you’ll need to drop another $1,200 for the computer and harness to make it run. It all adds up to some serious coin, but if you have the cash it’s certainly the way to go.

If you want to take a dip in the LS pond there’s another option. You see, GM has been stuffing LS variants into cars since around 1997. Given this, there are wrecked GM vehicles, fitted with LS cores, stacked deep at most salvage yards. By getting the engine cheap and putting in some effort, you’ll have more cash for the extras needed to get one running.

To try this out, we decided to find a decent salvaged engine and see what sort of power it could make with what amounted to a rebuild and a good camshaft. To save a few extra bucks and make swapping it into a car cheaper we also opted to slap a Holley carburetor on top. Now, what we did wasn’t the cheapest way to skin the Mouse. We dressed it up a bit with some ARP bolts, Holley valve covers, and a better-looking carburetor, but if you don’t mind exhaust manifolds and stock covers then you can knock this project out even cheaper, and make exactly the same power.

The core for our build was a 6.0L iron LQ4 engine out of a 2004 Silverado truck. When shopping, it’s important to do your homework. There are two 6.0L iron-block engines out there, the LQ9 (345 hp) and the LQ4 (300-325 hp). On the outside they are identical except for a small sticker on the back of the driver-side head, but that’s typically missing. The LQ9, is a high-output (HO) engine that is typically found in trucks such as the Silverado, while the lower-compression LQ4 is more often found in SUVs. If you know the VIN number of the donor vehicle the eighth digit will confirm what it had, a U for LQ4 or an N for LQ9. If the engine is out of the truck, and you don’t have a VIN number, then the best way is to use a borescope with a light and try to see the piston. LQ9s have flat-top pistons while LQ4 pistons have a distinctive dish.

Of course LQ9s will cost a bit more, but the 10:1 compression will make more power and still work fine on cheaper gas. The added compression of the LQ9 is worth about 10-15 horsepower, so if that’s not a big deal you can save money and find an LQ4 which comes in about half a point lower in compression. If your budget is even tighter you could look at one of the countless 5.3L or 4.8L engines piled up in salvage yards across the country, but the cost savings of the smaller displacement variants will also cost you horsepower and torque potential.

Our LQ4 set us back $900 complete with the harness, intake, exhaust manifolds, drive system, and a ton of other stuff we didn’t really want or need. All the extra bits went on Craigslist and netted us back $100, so the actual cost for our long-block core was $800. We found this locally, but there are all sorts of places online that sell them. Keep in mind that the prices vary quite a bit, so shop around.

A truck LS engine comes with a very ugly, and often difficult to work with, truck intake manifold. This means you have two options for your Chevy, buy a car-style LS intake manifold or go with a carburetor. The carb option looks great and saves cash since it doesn’t require an expensive harness, ECU, and tuning. However, you’ll still need coil packs to fire things up, but MSD makes a sweet little box to run them off the stock crank and cam triggers.

There are lots of ways to tackle a project like this, but we wanted ours to look nice, so we opted for aftermarket valve covers and fasteners. Forgoing these can save you cash, so it’s a personal preference deal. To illustrate this we listed the costs for our build and for one using less expensive options that would still net roughly the same power output.


1. Our starting point was this 2004 LQ4 6.0L engine salvaged from a 1500 Silverado. It had everything, including the wiring harness, ECU, pulley system, and coils. Of course, we didn’t want a lot of it so the extra parts were sold off, which brought us down to a final cost of just $800 for our core.


2. Here’s our 80,000-mile engine stripped down to its long-block. Don’t let the accumulated grime fool you, it’s a solid engine underneath.


3. The inside of the engine was in pretty decent shape. This is the part of buying used engines that’s a crapshoot. In our case, the only issue with the long-block was some surface rust in one cylinder where water must have leaked in. The block and other bits were taken over to Rancho Machine for some TLC. If you get lucky and end up with a super-clean engine you can just toss in new rings and bearings for an even less expensive rebuild. The hot tank set us back $40 while the hone added another $60 to the bill.


4. Along with the block we also had the heads gone through (resurface/valve job, $150) and, due to our larger cam, we also swapped to a set of COMP springs, seats, retainers, locks, and seals (PN 26918CS-KIT, $329). Next to the COMP spring you can see a stock style valve seal with integrated spring seat.


5. Unfortunately, many of our intake valves were beat to hell so we ordered up a set of stock replacements for $70. This isn’t common, so chances are that you won’t have to spend money here. The exhaust valves were in great shape.


6. The stock 24x reluctor crank was good-to-go, but we decided to have it polished for $40. Necessary? Probably not, but $40 was worth the peace of mind and cheaper than replacing main bearings prematurely.


7. Here’s our cleaned up 6.0L block back from the machine shop. Once back we stuffed in a fresh set of cam bearings (PN CH-10, $20) and gave it a few coats of Chevy engine orange paint.


8. Our freshly polished GM crank was then put in place. New main bearings were from Clevite (PN MS2199H, $140). There are cheaper bearings out there, but this isn’t a place where we like to skimp. To secure the crank we used the stock main caps and the original bolts.


9. The rods and pistons were cleaned up, but not disassembled since the pins are press fit. The LQ9 used a flat-top piston, which is why the 10:1 compression is a bit higher than an LQ4. Our LQ4 pistons have a very slight dish and hence a touch less compression. Running a thinner head gasket can get some of this lost compression back.


10. The weakest part of the stock rods, and the rotating assembly in general, are the rod bolts. Still, at the power level we’re aiming for swapping out the rod bolts is completely optional. We had these ARP pieces (PN 134-6006) left over from another project and decided to put them to use. That added a very optional $103 to our build, but we’re set if we want to toss a bit more power at the engine later on down the road.


11. Our engine was staying mostly stock, so if we were going to make more power, it was going to be with a good camshaft. After talking with the wizards over at Competition Cams (COMP) we came up with a custom-grind stick (PN 54-000-11, $407). Duration (at 0.050-inch) is 231/238 and the lift came in at 0.598/0.586. The full grind info is LS1 13045R / 3652R HR114+2.


12. With the cam slid in we installed the camshaft retention plate. Yeah, LS-series engines are just ridiculously easy to assemble.


13. To keep the costs down we reused the stock timing gear with the exception of a new timing chain (PN 222-4194, $28). The upper sprocket was secured using three ARP cam bolts (PN 134-1003, $8).


14. Since we were into the engine this far we dropped in a new high-volume Chevrolet Performance oil pump (PN 17801830, $79). Our donor engine had fairly low miles, so we could have cleaned up and reused the original, but the peace of mind was worth the extra cash.


15. With the new rings ($57) installed, we could start sliding the piston/rod assemblies into place. With LQ4 engines it’s really simple. They all go in, both banks, with the dot on the piston facing the front of the block. The design of the stock rods is such that they don’t have to face one way or the other. This was done to make assembly foolproof at GM.


16. New Summit rods bearings were added and the ARP bolts torqued to spec.


17. With a new cam we like to use new lifters. If your funds are tight, a new set of stock GM lifters (PN 12499225) will set you back around $135. The ones we chose were COMP High Energy roller lifters (PN 850-16, $224). These work with the factory plastic lifter trays and we feel are of a higher quality compared to the GM pieces. Our lifter trays were good to go, but if you need to replace any of them the GM part number is 12595365.


18. The valley cover that came on our LQ4 (or any early LS engine for that matter) is challenging to reuse since it has two large wells in the middle of it to accommodate knock sensors. We don’t need to run knock sensors and the holes are just a place for debris to accumulate. The options are to find a used, later-model (LS2/LS3/etc.) GM valley cover, plug the holes, or find an aftermarket solution like this slick billet cover from Custom Built Motors (CBM). It looks great and was bolted down using fasteners from our ARP master assembly kit. We opted for the stainless ARP six-point bolts ($210), but the black oxide version is less expensive at $148. These bolts fall into the “looks good” category, but it’s nice to not have to hunt for valve cover, oil pan, timing cover, engine mount, water pump, and other bolts.


19. GM head bolts are torque-to-yield, which means they can’t be reused. This leaves two options. The first is a new set of GM head bolts that will set you back around $70. Like the original bolts these are one-time-use bolts. Or you can go with a set of reusable ARP head bolts (PN 134-3609) like we found online for $170. To us, the extra $100 was worth it in the long run since we might try a head swap on this engine down the line. The MLS head gaskets came in our Fel-Pro master gasket kit (PN 2817, $380). That may seem like a big chunk of change, but it included every single gasket and seal needed to rebuild any Gen III LS engine.


20. The stock rockers were cleaned up and reused. A good upgrade, if you have the budget, would be COMP’s trunnion upgrade kit (PN 13702-KIT, $136). This would convert the rockers to captured roller trunnions. No extra power, but less chance of needle bearings blowing through your engine. The pushrods are stock.


21. We plan on swapping this engine into a first-gen Camaro so we knew the truck pan wouldn’t work. The fix was this Holley LS swap oil pan (PN 302-1, $380). The kit included the pan, pickup tube, O-ring, bypass plate, anti-slosh tray, drain plug, and oil filter adapter. We reused our stock windage tray.


22. Holley offers two pans. We chose the 302-1 ($375) pan for our application, but if you require more clearance their 302-2 pan is the hot ticket. It will require cutting down the windage tray (or replacing it with a GM F-body version PN 12558253). Either pan required us to buy a new dipstick and tube (PN 12634547 and 12625031), which cost $35 for the pair.


23. The new Holley carburetor intake came with Viton O-rings to seal to our LQ4’s heads.


24. The Holley Mid-Rise intake (PN 300-130, $256) has a 4150 square-bore carb mounting flange and is optimized for performance between 1,500 and 6,500 rpm. Our dual-plane is perfect for the street, but they also have a single-plane intake that will make a little more power on the top end and bit less on the bottom.


25. Another optional dress-up item we went with was a set of Holley LS valve covers. These ditch the coil pack brackets for a much cleaner look. The cost was $188 (PN 241-91) and the coils were secured using more fasteners from the ARP engine accessory kit.


26. On the back of the engine we installed the original cam sensor and a brass adapter in the oil port that gave us a 1/8-inch pipe port for the dyno’s oil pressure sender. The truck had an unwieldy steam crossover system so we replaced it with plugs on the back of the heads and a simpler crossover on the front. We had them on hand from another build, but expect to pay about $60 if you need to buy them.


27. If you squint, our carbureted LQ4 almost looks like a Gen I small-block, almost. For the dyno and eventual car transplant we’re running a set of Hooker LS Swap headers (PN 2275HKR, $534). These tubes feature 1.75-inch tubes flowing into 10-inch long, 3-inch collectors. Other options would be Hooker’s mid-length headers and cast exhaust manifolds ($386/$324), but both of these would hurt the power numbers a bit.


28. For a carburetor we opted for a Holley 670-cfm Ultra Street Avenger (PN 86670HP, $615). These are great for the street since they have a factory preset electric choke for easy starts and vacuum secondaries that are easy to tune with the included springs. The aluminum construction knocks the weight down about 43 percent and the carb came wet-flow tested and worked great right out of the box. If the wallet is lean, a good option is Holley’s 670-cfm Street Avenger (PN 80670, $431). It has the same cfm as the Ultra Street Avenger we used but a few less bells and whistles and comes in a vibratory polish finish instead of the trendy-cool black.


29. Instead of a distributor, all LS engine variants use a coil-on-plug arrangement. The good news is you don’t have to buy a coil; the bad news is that even though you don’t need an engine computer and harness you still have to fire the coil packs. Enter the MSD 6010 ignition controller ($357). This box plugged into our LQ4’s cam and crank sensors to properly time the coil firing. It also has some cool features like a two-stage rev limiter and a vacuum advance curve. There’s even a step retard in case we want to try some nitrous.


30. After a few pulls, Steve Brule at Westech Performance knocked down a best pull of 464 horsepower (at 6,300 rpm) and 437 lb-ft of torque (at 4,300 rpm). Even better news was the long, flat torque curve and how the engine pulled hard even past 6,500 rpm. This is certainly a long way from the 345 hp rating the stock LQ4 carried. Right now the stock truck heads are holding the power numbers back, but that’s another story for another time.

Our LQ4 Build
6.0L LQ4 Core $800
Machine Shop $290
COMP Spring Kit $329
Rings $57
Cam Bearings $20
Main Bearings $140
Rod Bearings $75
COMP Camshaft $407
COMP lifters $224
GM Oil Pump $76
Timing Chain $28
Holley LS Carb Intake $256
Holley 670 Ultra Carb $615
Holley Oil Pan $375
Dipstick and Tube $35
Flat Valley Cover $50
Fel-Pro Master Gasket Kit $380
MSD Coil Control $357
ARP Head Bolt Kit $170
ARP Engine Assy Kit $210
ARP Cam Bolts $8
ARP Rod Bolts $103
Total: $5,005

Budget-Minded LQ4 Build:
6.0L LQ4 Core $800
Machine Shop $290
COMP Spring Kit $329
Rings $57
Cam Bearings $20
Main Bearings $140
Rod Bearings $75
COMP Camshaft $407
GM lifters $135
GM Oil Pump $76
Timing Chain $28
Holley LS Carb Intake $256
Holley 670 Street Avenger $431
Holley Oil Pan $375
Dipstick and Tube $35
Flat Valley Cover $50
Fel-Pro Master Gasket Kit $380
MSD Coil Control $357
GM Head Bolt Kit (Using stock bolts where possible) $70
Total: $4,311


ARP (Automotive Racing Products)
Ventura , CA 93003
Don Lee Auto
Cucamonga, 91730
Summit Racing
Akron, OH
Westech Performance
Mira Loma, CA 91752
Bowling Green, KY 42101
Southfield, MI 48034
MSD Performance
El Paso, TX 79936
Competition Cams
CBM Motorsports



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