Tech Corner: Selecting the Proper Camshaft for a Beloved Hot Rod

Tech Corner - Though welding skills range from basic to advanced, we are going to label this mini-series as Advanced because our hope is to build your knowledge to a point that, with some practice, you can feel confident tackling more detailed projects.Picking the proper camshaft is one of the most important parts of building an engine. It essentially controls how the engine wants to breathe and dictates how and when the power is produced along the power curve. When an engine has only one purpose in mind, it eliminates a lot of grey area. For instance, a race engine will be living high in RPM’s and have a constant demand for as much fuel as possible. But what about a car that you drive around town during the week, and only hits the track on the weekend? Here we’ll examine the steps you should take when picking the right cam for your street rod.

The customer has to be honest with themselves and what the purpose of their car is. Are they looking for a lopey idle or a cam to get the best performance out of their combination? You usually can’t have both of those things, pick one and you’ll compromise on the other,” said John Potucek, Product Master Data at Keystone and longtime weekend warrior at the track. “When I say be honest with yourself, I mean, look at your combination as what you have, not what you dream it to be. If you run a 2200 stall converter and 3.55 gears, don’t pick a cam designed for 3500 stall and 4.56 gears. If it’s a daily driver and you run a dual plane intake, don’t pick a cam that is designed for 3500-8000 RPM. Choosing a cam that doesn’t optimize the parts you have is the biggest mistake I see and can be very depressing for the customer.”

Go Big or Go Home… Or Should You?

When building up a muscle car it’s always tempting to up the ante. You’ve got a big V8 in a big car, so naturally you’re going to want to make as much power as possible. This is the American way, right? And really, that’s the spirit of these types of vehicles. The trick, however, is to stay within reason. A large camshaft with big lift and higher duration will make more power. And it may be tempting to reach out for these bigger cams. But you have to pay attention to where the power is being made. Large cams are meant to make power in higher RPM’s; the bigger the camshaft the further out it will want to make power. But a street rod will be spending a lot of time cruising around town. Even if it has an engine that could spin out to a high redline, you won’t be using all of that power running to work or the grocery store. The engine will likely be spending most of its life up to and around 3000 RPM. 

We did mention that street rods will find their place on the track from time to time. Because of this, you don’t want to go with too small of a cam either. You’re going to want to grab something that has a little more beef than a docile stock cam without going too far. 

Sometimes Less is More

Although the camshaft may be considered the heart of the engine, it isn’t responsible for all of the engine’s capabilities. A massive cam may work to move as much power as possible, but if the entire platform can’t support the flow, it simply won’t perform. In this instance, less may be more when it comes to the cam. Don’t be afraid to let the cylinder heads, intake manifold, exhaust and even the rocker arms take on some of the responsibilities of making power.

It’s all about finding the middle ground. After all, that’s where a street rod lives– somewhere between comfortable and radical. Something you can rely on to perform both day to day and on the track. They bear mid-level engines and the camshaft really should match up to that.

The good news for street rod enthusiasts is that we have experienced suppliers on our side. Ones who have been in the game for generations. Comp Cams, Edelbrock, Isky, Crane, and Lunati have all been producing cam grinds for various applications over the years. This gives enthusiasts the chance to really feel out what offerings are available, along with how well they perform and where they make their power.

Find a Happy Medium

You really can have your cake and eat it too. A builder simply needs to consider exactly what their engine is capable of and then pick out the camshaft that will best deliver what they’re looking for. That could even entail taking things a step further and having something custom ground. “For most street cars or mild street/strip cars there will be an “off the shelf” cam to fit your needs. For someone seeking maximum performance they can have a professional “spec” them a cam for their setup usually for a small fee. Then a company like Comp Cams can grind the cam for them to the custom specs,” added Potucek. Shoot for a happy medium somewhere between the track and the street – the middle ground will serve you well.

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