One of the greatest things about the LS engine family is that anyone can switch cams without removing the intake manifold or cylinder heads, but you should make sure that you have the proper nose adaptor which fits an LS camshaft. Keeping the camshaft straight as it moves through the bore so the lobes don’t scrape the cam bearings.

With today’s Internet dyno jockeys, bench racers and talk room engine experts, separating the facts from fiction on late model cam swaps can be both intimidating and confusing. That’s why Virginia Speed in Virginia Beach, VA, has been busy in recent months sorting out camshafts for LS3 street applications.  With the difference in architecture between the first gen Chevy small block and the LS series of engines, the thought process behind what made one engine work best may not be the same with the other.

“A lot of people call in looking for the most peak horsepower they can find,” said Shawn Miller who is the Shop Manager/Engine Builder at Virginia Speed. “To be realistic, peak horsepower is really just a tool for bragging rights and sales. Before everyone had chassis dynos, the only way people could really compare was by taking your car out to the local drag strip to compare time slips. Nowadays, people can run their cars on a chassis dyno to compare peak horsepower figures, but that doesn’t mean tell you if the car has the mid- range power you need for it to drive well or feel good.”

Virginia Speed’s test mule was a L99 6.2 V-8 from a 2010 Camaro that was converted back to LS3 specs by removing the active cylinder deactivation.  Both engines share the same block, cylinder head and intake manifold design elements. The LS3 powers the top-of-the-line Camaro while the L99 is used in automatic equipped cars.

Thorough testing of new am profiles is an important process in validating what looks good on paper – and on the computer screen. It also eliminates a lot of guesswork, time and money for the end user. For many looking into making a cam swap, the most common mistake in choosing the right grind lies in being too aggressive. Cam profiles that produce the biggest numbers are most often intended for high rpm ranges and don’t do as well in street driven engine applications because of the rumpity-rump idle quality – at the sacrifice of driveability and torque. Part of that is due to an increase in duration or decrease in lobe separation angle because the valve overlap makes fueling inconsistent at idle. Drastic changes in the camshaft profile can also require wholesale changes throughout the rest of the valvetrain as well, such as new valve springs, rocker arms and pushrods.

“When it comes to camshaft changes, these engines are very particular,” Shawn said. “The cylinder head on the LS3 has a very big intake, so you have to be aware of potential valve to piston clearance issues. With a flat top piston, you have to be very careful about how big of a camshaft you put in it duration-wise. You also have to be careful because they have a very big intake runner in the cylinder head, so if you try to over cam the thing, it’s going to drive like a piece of junk on the street. It took a lot of trial and error over time to get these things to drive nice and still make good power.”