Chopacabra Cam Install on a 5.3 LY5 — Full Walkthrough

The 5.3L LY5 is one of the most popular engines in the LS truck world — reliable, plentiful in junkyards, and a great platform for budget builds. But stock, it's tuned for fuel economy and low-end torque. If you want to wake it up without going forced induction, a cam swap is the single best bang-for-buck mod you can do.

I went with the Chopacabra cam, and after running it for a few months, I can say it transformed the character of the engine. Here's the full walkthrough of the install on my 5.3 LY5.

Why the Chopacabra Cam?

There are dozens of cam options for the LS platform, but the Chopacabra stands out for truck and daily-driver builds. It's designed to work well with the stock LY5 heads, stock valve springs (in most cases), and a stock torque converter. That means you're not falling down a rabbit hole of supporting mods just to make the cam work.

The Chopacabra gives you a noticeable bump in mid-range and top-end power while keeping a streetable idle. It's not a drag race cam — it's a "make the truck actually fun to drive" cam. Expect gains in the neighborhood of 30–40 horsepower at the wheels with a proper tune.

Tools & Parts You'll Need

Before you start pulling things apart, gather everything. Nothing kills momentum like a parts run mid-job.

Tools

• Standard socket set (metric — 8mm through 18mm)
• Torque wrench (ft-lb and in-lb)
• Harmonic balancer puller
• Cam phaser lockout tool (or a zip tie in a pinch — more on that below)
• Magnetic pickup tool
• Breaker bar
• Engine hoist or support bar (if pulling the motor — not required for in-vehicle)
• Gasket scraper and brake cleaner

Parts

• Chopacabra camshaft
• Timing cover gasket set
• New cam bolts (reusing the old ones is asking for trouble)
• Assembly lube (critical — don't skip this)
• Fresh oil and filter (you'll want to change oil immediately after break-in)
• Optionally: new lifters, pushrods, and valve springs depending on your build goals

Teardown — Getting to the Cam

If you're doing this in the truck (which I did), you'll need to remove the following to access the timing cover and cam:

1. Drain coolant and disconnect the upper and lower radiator hoses.
2. Remove the radiator fan and shroud. Four bolts hold the fan clutch to the water pump. Remove the shroud bolts and pull the whole assembly as one unit.
3. Remove the serpentine belt. Release tension with a 15mm wrench on the tensioner.
4. Pull the water pump. Four bolts — be ready for residual coolant.
5. Remove the harmonic balancer. This requires a puller. Do not pry it off — you'll damage the crank snout.
6. Remove the timing cover. Clean the mating surface thoroughly. Every bit of old gasket material needs to come off or you'll have an oil leak.

At this point you can see the timing chain, cam sprocket, and the front of the camshaft. Take a breath — you're past the hardest part of teardown.

Old Cam Removal

Before pulling the old cam:

1. Rotate the engine to TDC on cylinder #1. Align the timing marks on the crank and cam sprockets.
2. Remove the cam sprocket bolts (three bolts, 10mm). Support the timing chain so it doesn't drop into the oil pan.
3. Remove the cam retainer plate (if equipped).
4. Slowly slide the cam forward and out. Go slow — the cam lobes can nick the cam bearings if you're careless. Rotate it gently as you pull. This is the step where patience pays off.

Pro tip: Thread a long bolt into the front of the cam to use as a handle. It gives you much better control when sliding it out (and back in).

Installing the Chopacabra Cam

This is the fun part.

1. Coat the cam lobes and journals generously with assembly lube. Every lobe, every journal. This is what protects the cam during initial startup before oil pressure builds. Do not skip it. Do not use motor oil as a substitute.
2. Carefully slide the new Chopacabra cam into the block. Same deal as removal — go slow, rotate gently, and don't let the lobes contact the bearings at an angle.
3. Reinstall the cam retainer plate and torque the bolts to 18 ft-lbs.
4. Reinstall the timing chain and sprocket. Align the dots — crank dot at 6 o'clock, cam dot at 12 o'clock (or per the Chopacabra instructions if they specify an advance).
5. Torque the cam sprocket bolts to 26 ft-lbs.

Reassembly & Torque Specs

Reassembly is teardown in reverse, with some critical torque specs:

• Timing cover bolts: 18 ft-lbs
• Harmonic balancer bolt: 240 ft-lbs (yes, it's a lot — use the breaker bar)
• Water pump bolts: 11 ft-lbs (don't over-torque — it's aluminum)
• Cam sprocket bolts: 26 ft-lbs

Use a fresh timing cover gasket. Apply a thin bead of RTV at the oil pan-to-block junction where the timing cover meets it — this is a known leak point on LS engines. Let the RTV tack up for 10 minutes before tightening the cover down.

First Start & Break-In

This is where people ruin brand new cams. The break-in procedure is non-negotiable:

1. Use break-in oil or conventional oil with a high ZDDP content. Do not use full synthetic for break-in.
2. Prime the oil system. If you have a priming tool, use it. Otherwise, crank the engine with the fuel fuse pulled until you see oil pressure on the gauge.
3. Start the engine and immediately bring RPMs to 2,000–2,500. Hold it there. Do not let it idle.
4. Vary RPMs between 2,000 and 3,000 for 20 minutes. This is the critical cam break-in window. The lobes and lifters need consistent splash oiling and contact pattern development.
5. Shut it down, let it cool, then change the oil. The break-in oil will be full of metal particles. Get it out.

I cannot stress this enough: do not idle the engine during break-in. Low RPM = low oil volume to the cam = flat lobes and a trashed cam within 500 miles.

Results & Final Thoughts

After the break-in and a proper tune (I went with a mail-order tune from a reputable LS tuner), the difference was immediately obvious. The truck pulls harder through the mid-range, has a nice lopey idle that's not obnoxious, and honestly just sounds better. It's not a built race motor — it's a truck that's fun to drive now.

Dyno numbers (before and after, rear-wheel):

• Stock: 248 hp / 292 lb-ft
• With Chopacabra cam + tune: 286 hp / 318 lb-ft

That's a 38 hp and 26 lb-ft gain from a cam and tune alone — on stock heads and stock springs. For the money, there's nothing else on a truck LS that gives you this kind of return.

If you're on the fence about a cam swap on your LY5, just do it. It's a weekend job if you're comfortable turning wrenches, and the transformation is worth every hour in the garage.

Planning your own cam swap? Check back for more LS build content — I've got valve spring and header upgrades coming next.