High-Lift vs Low-Lift Camshafts: When You Actually WANT to Make LESS Power with an LS or LT Motor

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Switching to a lower-lift camshaft costs only a few ponies, but rewards your engine with a healthier, longer-lasting valvetrain. (Here’s why!)

I love hanging out with Kohle and the team over at American Heritage Performance. Full disclosure, AHP is a CorvetteForum vendor. But after profiling them for the site and filming a C8 Corvette exhaust install video over there, I relish my time at the shop. Why? Because not only do they wrench on modern Corvettes, but they also manufacture and install race-caliber LS engine components. Primarily for the LS7, but they do lots of stuff for the LS and LT platforms. In fact, you’ll see AHP parts on the world’s fasted naturally aspirated C6 Z06 —

Anyway, the reason I love hanging out there — besides getting to hear track-prepped LS7s screaming from longtubes — is that I learn something new every time.

Case in point, I recently had them double-check the damper install on my LS3-swapped Buick Roadmaster, which we’re chronicling over HERE on LS1Tech.com. (I was worried I had made a mistake, but they confirmed my install had been correct.) Coincidentally, Kohle was working on a bit of an experiment regarding high-lift vs low-lift camshafts on a customer’s engine. So we sat down for an interview on the subject —

High-Lift vs Low-Lift Camshafts (Dyno Tested Results)

I’ll let the above interview speak for itself, but here’s a quick rundown.

Kohle had a customer with a 442ci LS7 running a high-lift camshaft and American Heritage Performance Archangel heads. And after about 25-30,000 miles of hard driving and track action, the engine broke a rocker arm and the springs needed some attention (despite the overall engine health remaining strong).

After giving the engine a little refresh, the customer asked Kohle what he would have to sacrifice to avoid having to do similar refreshes every 30,000 miles. So Kohle teamed up with Cam Motion to run a little experiment.

1. Set a baseline dyno curve with the high-lift camshaft
2. And then follow it up with a low-lift camshaft that’s as close as possible in terms of its design

In other words, how much power would you be sacrificing to maintain valvetrain stability? Here are the two tests —

The result? Roughly 20 fewer horsepower and 10 fewer ft.-lbs of torque.

Which is surprising for a couple of reasons (more so for me than for AHP, mind you). If you look at the dyno graph in the interview video, the power numbers are nearly identical until about 4,800 RPMs. Also, the lower-lift camshaft makes peak power about 100 RPMs quicker than the high-lift camshaft. Overall, Kohle was expecting about a 25 hp drop and was glad to see it an even smaller number. A number that would be hard to feel for most non-pro drivers.

Should You Buy a Low-Lift or High-Lift Camshaft?

In the enthusiast world where many folks are chasing every last bit of power — with tunes and fuel and exhaust and all sorts of go-fast parts — it’s refreshing to hear a performance shop say to a customer… “hey, we can build you a car with LESS power because it means you’ll have less maintenance and it’s a pretty small power tradeoff.” All in the sake of longevity.

Which brings me to Kohle’s personal recommendation (one that I share)…

Unless you’re going full racecar — unless you’re competing with money and prepared to inspect and refresh your engine as needed — go with the lowest possible lift camshaft for your build. You can still get chop, by the way, as classic cam sound is based on duration and overlap, not lift. But your goal should be to protect your valvetrain, which translates into —

• Less maintenance
• Less potential for valve guide wear (which means replacing or reworking your heads)
• Overall, a longer-lasting engine

Trading 20 ponies for the longevity and driveability of a street car seems like a no-brainer to me. But your take might be different. Go for crazy power if you want. We don’t mean to knock anyone’s goals, of course. Just know the complications that higher-lift camshafts add to the equation, which require extra vigilance.

Good luck out there with your builds. And, of course, don’t forget to share them all in the forums!

Photos: Michael S. Palmer