One quick way to make power with any LS engine, regardless of displacement, is with a simple cam swap. The cylinder heads are so good that a simple 6.0L iron block truck engine can make over 475 hp with just a slightly bigger camshaft. Add a good EFI intake manifold and you can easily make over 500 hp.
Our 6.0L came out of a 2003 Chevy pickup with a ton of miles on it but it’s still ready to make some serious power. We’ve added a Sniper fabricated intake manifold, throttle body, and a pair of mildly ported 5.3L West Coast Racing Cylinder Heads cathedral port heads along with a mild cam. This package made decent power but, being good gear heads, we wanted more.
Comp has a brand new line of Low Shock Technology (LST) cams so we thought we’d bolt one in place and show just how easy it is to swap camshafts in the LS engine family. Our early Gen III engine places the cam sensor at the back of the engine so this makes the swap even easier since there is no cam sensor equipment or variable valve timing (VVT) equipment to get in the way.
We did not degree this cam as part of this story, but it’s always a good idea to check the cam position, especially with high performance camshafts with lots of lift that can tighten the piston-to-valve clearance.
You will notice in the procedure that it’s not necessary to remove the oil pump to swap the cam. However, if you will be changing the timing gears and chain, then the pump will need to be removed. There’s a trick to reinstalling the oil pump that will save time and effort. The factory will tell you that to install the oil pump, you must mount the pump and then remove the cover bolts and carefully set the clearance with a pair of feeler gauges. With the clearance set, then torque the mounting bolts to the block.
Instead of making all that effort, Kenny Duttweiler showed us this trick that saves a ton of time. Install all four oil pump bolts to the block with only slight pressure. Then turn the engine over three to four revolutions using the harmonic balancer bolt. This will align the internal oil pump gear around the crank hub without removing the oil pump cover. We actually checked the clearance the first time we did this and it works. Torque the oil pump bolts to their spec and you’re ready to move on.
The swap is easy and on the dyno, we’ve accomplished this entire process in under 30 minutes with only a couple of specialty tools that aren’t expensive and we didn’t even work up a sweat. This is just one more reason the LS engines are so popular.
Our test mule for this story is an iron block 6.0L LS engine with a set of 5.3L heads ported by our friends at West Coast Racing Cylinder Heads fitted with a set of Holley valve covers and fed by a Sniper fabricated manifold with a 92mm Sniper throttle body.
We added this Holley lifter valley cover plate that sits underneath the Sniper intake just to dress our engine up a little. It’s not necessary to remove the intake manifold or the lifter cover to swap the cam.
The most challenging part of this swap might be removing the harmonic balancer. These are three different balancer puller tools. On the left is a Summit kit for stock balancers. In the middle is a puller kit for all engines with an LS adapter for aftermarket balancers that feature three internal 3/8-inch fine thread mounting holes. The tool on the right is a three-jaw puller that will work for OE balancers that don’t have bolt holes.
The Holley valve covers eliminate those unsightly coil brackets but we still have to remove the coils to remove the valve covers. The Holley valve covers use a 9mm socket head on the valve cover hold-down bolts.
Loosen and remove the eight rocker hold down bolts on each cylinder head and then remove the rockers and pushrods. Our little electric 3/8-inch drive gun makes this quick work.
With the spark plugs removed to make it easier to turn the engine over, rotate the engine at least four full revolutions. This will push the lifters up into the plastic holders. The holders will retain the lifters while the cam is removed.
This is what the lifter holders look like. They will capture the lifters and keep them away from cam to allow removing the cam without having to remove the lifters from the engine.
You don’t have to drain the coolant from the block, but it makes things less messy when removing the water pump. The water pump gaskets can be reused if they are not damaged.
Stock LS engine balancers do not have threaded bolt holes to allow removing, so we use a three-jaw puller to do the job. Summit Racing also sells a specific LS balancer removal and install tool to make this easier.
Our engine was fitted with an aftermarket harmonic balancer that does have the three bolt holes, allowing us to use a more common harmonic balancer puller. This generic tool will require a specific LS mandrel. Our engine is also fitted with a reusable ARP crank bolt.
The front cover is retained with 10 front cover bolts that use 10mm socket. There are two bolts that come in from the bottom through the oil pan that must also be removed. The oil pan does not have to be loosened or disturbed to remove the front cover.
Turn the engine over with the crank bolt until the marks on the cam and crank gears are lined up across from each other. Note that the oil pump does not have to be removed to do this.
With the dots aligned, remove the three cam gear bolts (late LS engines use a single bolt), remove the cam gear, and allow the chain to settle on top of the crank gear. Loosening the cam bolts might move the rotating assembly and if so, just reposition the two dots until they are properly aligned.
All LS engines use a cam retainer plate that also seals the oil galleries, so this cover must be removed to access the camshaft.
On older LS engines, those plastic retainers may not be strong enough to hold the lifters up. This trick is important since if the lifters fall out of the holders, it will require pulling the oil pan to retrieve them and pulling the heads to replace them! Our pal Steve Brulé at Westech Performance likes to use a pair of 5/16-inch long aluminum rods that fit through both lifter galleries to hold the lifters in place. We used a 5/16-inch steel rod about four feet long from the hardware store. Sometimes this long pin may require a flat portion the entire length to fit properly but our engine didn’t require this. We shot this photo after removing the cam since our engine is fitted with new plastic retainers.
We used a longer water pump bolt in the cam to help leverage the first two journals out of the engine to help pull cam.
Place assembly lube on the new cam. We really like Driven’s new assembly lube. Slide the cam carefully into place just like any other engine. A long metric bolt may be necessary for the last journal length. Try to avoid nicking the cam bearings.
Don’t forget to re-install the cam cover. This also seals the main oil galleries as well as limits cam movement. We torqued the bolts to factory specs listed in our torque specs chart.
After installing the cam cover, install the cam gear and chain and line up the marks with the crank gear.
We prefer to apply a few drops of locking compound on the threads to ensure they stay tight.
It’s always good to torque the cam bolts to ensure they are fully seated and secure to the cam.
Before installing the front cover, place a small dab of RTV at each corner of the oil pan where the front cover gasket is at right angle to the oil pan gasket. This will minimize any leaks. Install the bolts but leave them finger tight.
There are no alignment pins for the front timing chain cover, so Mr Gasket makes a slick tool to align the front seal to the crankshaft. Slip the tool over the crank snout and then torque the front cover bolts in place. With all the bolts tight, remove the tool. The other tool is a homemade piece we used before the Mr Gasket tool came along. If you have an old LS truck engine balancer that you don’t need, cut off the balancer and hone the inside of the hub with a sanding roll until the hub will slide over the crank snout that creates a homemade tool to align the front cover. Torque the cover bolts with the alignment tool in place.
Now reinstall the harmonic balancer using a small amount of anti-seize on the inside and a little engine oil for the seal on the outside diameter of the hub. We’re using an ARP crank bolt but if using a stock bolt, always use a new GM crank bolt as these fasteners are torque-to-yield. Follow that with replacing the water pump.
Moving to the top of the engine, replace the pushrods and rockers and torque the rocker bolts in place to the factory spec. This will push the lifters back into place on the cam. Next we also reinstalled the valve covers and the coils. If we were planning on tearing this engine apart on a regular basis, a set of metric studs to mount the coils would save wear and tear on the valve covers.
Tightening the fitting from the Holley steam line into the water pump was the last step and with that our 6.0L is re-assembled with its new cam ready to rumble!
