Building a 5.7 HEMI engine with long tube headers on a budget under $2,500 is a real possibility for any dedicated gearhead. The Gen III HEMI platform offers an incredible performance-to-dollar ratio, making it a favorite for swaps, upgrades, and full builds. With careful planning and smart sourcing, you can achieve a stout, reliable power plant that punches well above its weight class. This guide breaks down each component, offers realistic pricing, and shows you where to find the best deals to keep your project affordable without sacrificing quality.

Understanding the 5.7 HEMI Engine

The 5.7-liter HEMI, introduced in 2003 for the Dodge Ram and later appearing in Chrysler and Dodge vehicles, revived the legendary hemispherical combustion chamber design. The “hemi” shape allows for a more efficient burn, reduced heat loss, and a larger valve area compared to conventional wedge-shaped heads. Factory ratings typically land between 340 and 395 horsepower depending on the year and application, with plenty of torque down low. The engine's iron block (later aluminum in some trucks) and robust bottom end can handle significantly more power with simple upgrades. Adding long tube headers is one of the most cost-effective ways to unlock airflow, reduce restriction, and gain 20 to 40 horsepower at the wheels, especially when combined with a proper tune.

Key Components for the Build

To reach your target under $2,500, you'll need a balanced combination of proven parts. Every component must deliver results without unnecessary frills. Here are the core pieces:

1. The 5.7 HEMI Long Block or Short Block

The heart of the build is the engine itself. You can source a complete used 5.7 HEMI from a salvage yard, a private seller, or an online marketplace. A donor engine from a 2003–2008 Dodge Ram 1500 or a 2005–2010 Charger/Challenger often sells for $800–$1,500 depending on mileage and condition. If your budget is tight, aim for a complete long block with intake, exhaust manifolds, and accessories — you can sell off parts you don't need to recoup some cash.

2. Long Tube Headers

Long tube headers replace the restrictive factory exhaust manifolds. Primary tube length and diameter matter: 1¾-inch primaries with a 3-inch collector are popular for mild to moderate builds. For a budget build, consider brands like Pace Setter or JEGS house brand, which offer solid construction at a lower price point than premium brands like American Racing or Stainless Works. Expect to pay $350–$600 new, but you can often find used sets on forums for around $250–$400.

3. Performance Camshaft

A cam upgrade is the single biggest power adder after headers. A mild performance cam in the 220–230 degree duration range (at 0.050-inch lift) works well with long tubes and keeps drivability reasonable. Look for a cam kit from brands like Comp Cams or BTR that includes lifters and springs. Budget $250–$400 new; used cams can drop to $150–$250 if you're patient.

4. High-Flow Intake Manifold

The factory intake manifold on early 5.7 HEMIs is actually quite good, but a ported version or a aftermarket unit like the Hughes Performance ported manifold or a budget-friendly knockoff can improve top-end flow. For under $2,500, you can often skip a new intake and instead port the factory unit yourself or find a used aftermarket piece for $200–$350.

5. ECU Tune

Without a proper tune, you'll leave power on the table and risk running lean. A handheld tuner like the DiabloSport i3 or HP Tuners software (if you have access) can cost $300–$500 new. However, many performance shops offer mail-order tunes for as little as $100–$150 if you send them your stock PCM or a core unit. Alternatively, source a used Predator tuner from forums for around $150–$200.

6. Supporting Hardware & Gaskets

Don't overlook gaskets, bolts, spark plugs, and fluids. A complete gasket set runs $50–$80. ARP header bolts are worth the extra $20–$30. Factor in about $50–$100 for miscellaneous items like oxygen sensor extenders, antifreeze, and oil.

Detailed Cost Breakdown

Below is a realistic budget that hits under $2,500. Prices are based on average market values from salvage yards, online retailers, and private sellers as of early 2025. You can cut costs further by buying used or bundling parts.

  • 5.7 HEMI Engine (complete, used, low miles): $1,200–$1,400
  • Long Tube Headers (used or budget brand): $350–$450
  • Camshaft & Lifters (used or budget kit): $200–$300
  • Intake Manifold (port factory or used aftermarket): $100–$250
  • ECU Tune (mail-order or used tuner): $100–$200
  • Gaskets, Bolts, Spark Plugs, Fluids: $80–$120
  • Miscellaneous (spark plug wires, vacuum lines, etc.): $50–$80

Adding the high end of these ranges gives approximately $2,600. By scouring classifieds, using part-out deals, and negotiating, you can easily shave $200–$300 off. Many builders have completed this exact combo for under $2,300.

Where to Find Parts on a Budget

Smart sourcing is the key to staying under budget. Do not pay retail for every part. Here are the top channels:

Online Retailers and Clearance Sections

Summit Racing and JEGS regularly run sales, clearance items, and free shipping promotions. Sign up for their newsletters. Also check their scratch-and-dent or overstock sections for headers and intakes at steep discounts.

Salvage Yards and Part-Outs

Look for 5.7 HEMI donor vehicles at local junkyards using sites like Car-Part.com. You can often negotiate a complete engine for under $1,000 if you remove it yourself. Many Mopar-specific forums have part-out threads where sellers break entire vehicles — an excellent source for intake manifolds, sensors, and even headers.

Facebook Marketplace and Craigslist

Private sellers often undercut retail by 30–50%. Search for “5.7 Hemi long block” or “LS swap Hemi take-out parts.” Beware of high-mileage units or engines with known issues (tick, knock). Always ask for compression numbers or a running video.

Online Forums and Facebook Groups

Forums like LXForums, RamForum, and ChallengerTalk have dedicated buy/sell sections. Members often sell used cam kits, tuners, and headers at fair prices. Pay via PayPal Goods & Services for protection.

Installation Tips and Considerations

This build requires solid mechanical skills and a decent tool collection. Here are essential tips to avoid headaches and extra costs:

  • Plan your order of operations — Install the cam before bolting on the intake and headers. Access to the timing chain and oil pump is much easier with the front of the engine exposed.
  • Use ARP header bolts — Standard bolts loosen over time with heating cycles. Quality bolts plus lock washers save you from a gasket leak later.
  • Check piston-to-valve clearance — If you choose an aggressive cam, verify clearance with clay. Most mild designs clear fine, but it's a cheap insurance step.
  • Long tube headers may require minor modifications — On some chassis (especially A-body swaps), you may need to dimple a tube or shift the transmission crossmember. Measure twice, cut once.
  • Tune is mandatory — Running long tubes without a tune can cause a check engine light from the rear oxygen sensors. Disable them or use spark plug non-foulers as a temporary cheat, but a proper tune from a reputable shop like Hemifever Tuning is the best route for drivability and power.
  • Label everything — Take photos during disassembly to help with reconnection of vacuum lines, wiring, and coolant hoses.

Performance Expectations and Conclusion

With this budget build — long tube headers, a mild cam, a ported intake, and a tune — you can expect roughly 350–380 horsepower at the rear wheels (depending on the engine's baseline and the header quality). That's a 50–80 horsepower increase over a stock 5.7 HEMI, which translates to low 13-second quarter-mile times in a 3,800-pound vehicle. Torque will be strong from 2,500 rpm to 6,000 rpm, making it a blast for street driving and occasional track days.

The beauty of this project is its upgradability. Later, you can add a larger throttle body, cylinder heads, or a supercharger. Starting with a solid bottom end and good exhaust flow gives you a foundation that can handle 500+ horsepower down the road.

Building a 5.7 HEMI with long tube headers for under $2,500 isn't a pipe dream — it's a proven, repeatable project. Stick to used parts, watch for sales, and do your own labor. The result is a custom, high-performance engine that costs less than many crate options. Happy wrenching!