The GM Performance Parts 350 crate engine remains one of the most popular choices for enthusiasts seeking a reliable power upgrade without the complexity of a full custom build. Originally introduced as an evolution of the legendary small-block Chevy, this crate engine delivers proven performance, parts availability, and a straightforward installation process that appeals to both seasoned mechanics and first-time engine swappers. In this guide, we cover everything you need to know about upgrading to the GM Performance Parts 350 crate engine — from horsepower figures and cost breakdowns to detailed installation advice and supporting modifications.

A Brief History of the Chevy Small-Block 350

The small-block Chevrolet engine family debuted in 1955 with a 265 cubic inch displacement and quickly became a staple of American performance. By 1967, the 350 cubic inch version appeared in the Chevrolet Camaro and soon powered everything from pickup trucks to Corvettes. Its simple pushrod design, cast-iron block, and generous aftermarket support made it the go‑to platform for hot rodders. The GM Performance Parts division took this heritage and engineered crate engines that offer reliable, turn-key performance. The modern 350 crate engines benefit from years of refinement, including improved cylinder heads, roller camshafts, and precision balancing — all while retaining the same basic architecture that made the original so successful.

Understanding the GM Performance Parts 350 Crate Engine

GM Performance Parts offers several 350 crate engine variants, each tailored to different performance goals. The core design remains a 5.7‑liter (350 ci) V8 with a 4.00‑inch bore and 3.48‑inch stroke, using a cast-iron block and aluminum or cast-iron cylinder heads depending on the model. These engines are built in GM’s dedicated crate engine facility, tested for proper oil pressure, compression, and leak-down before shipping.

Available Models and Specifications

Below are the most common GM Performance 350 crate engines and their key specs:

  • GM Performance 350 HO (19355705) – 330 hp / 380 lb-ft torque. Features aluminum Vortec‑style heads, a steel roller cam with 0.435‑inch lift, and a dual-plane intake manifold. Ideal for street cars and light trucks.
  • GM Performance 350 Ram Jet (12499438) – 350 hp / 400 lb-ft torque. Includes a unique intake system with hidden injectors, electronic throttle body, and ECM. Modern EFI convenience with a classic look.
  • GM Performance 350 ZZ4 (24502609) – 355 hp / 405 lb-ft torque. Known for its forged steel crankshaft, high‑flow aluminum heads, and a more aggressive roller cam. Popular for high‑performance street and strip builds.
  • GM Performance 350 Fast Burn (12499435) – 385 hp / 410 lb-ft torque. Uses a larger 1.6‑ratio rocker arm, 64‑cc combustion chambers, and a hot cam profile. Best suited for cars that see frequent track use.

All variants share the same external dimensions and bellhousing pattern, making them direct replacements for any vehicle originally equipped with a small-block Chevy engine.

Power Advantages of the Crate Engine Upgrade

Replacing a worn or low‑output factory engine with a GM Performance 350 crate engine delivers immediate, measurable improvements. The most noticeable change is the increase in low‑end torque — the 350’s torque curve peaks early, often by 2,500‑3,000 rpm, which transforms how the vehicle accelerates from a stop. For trucks and SUVs, this means stronger pulling power without excessive gear hunting. For muscle cars and street rods, the extra horsepower translates to quicker quarter‑mile times and more thrilling top‑end pulls.

Real‑World Performance Gains

  • 0‑60 mph times typically drop by 1‑2 seconds compared to a stock 250‑hp 350.
  • Quarter‑mile ET reductions of 0.5 to 1.0 second are common with no other changes.
  • Dyno‑validated rear‑wheel horsepower increases of 80‑120 hp over a typical low‑compression 1970s 350.
  • Improved throttle response from a modern roller cam profile and optimized intake/exhaust flow.

These gains are achievable because the crate engine is optimized as a system — the camshaft, cylinder heads, intake, and pistons are matched from the factory. You avoid the guesswork and potential mismatches common in piecemeal builds.

Cost Considerations: More Than Just the Engine

Budgeting for a crate engine upgrade goes beyond the engine price tag. While the GM Performance 350 crate engine itself costs between $5,000 and $8,000 depending on the variant and retailer, you must also account for installation labor, replacement parts, and incidental costs. Below is a typical breakdown.

Engine Pricing by Model

  • 350 HO (330 hp) – approximately $5,200–$5,800.
  • 350 Ram Jet (350 hp) – approximately $6,500–$7,200 (includes EFI system).
  • 350 ZZ4 (355 hp) – approximately $5,800–$6,500.
  • 350 Fast Burn (385 hp) – approximately $7,500–$8,000.

Prices vary between vendors such as Summit Racing, JEGS, and authorized GM dealers. Always check for shipping costs and core charges if returning an old engine.

Installation and Supporting Costs

  • Labor for professional installation: $1,000–$2,500 (8–20 hours depending on vehicle complexity).
  • Gaskets, fluids, and hardware: $150–$300 (intake gasket set, exhaust gaskets, oil filter, coolant, etc.).
  • Upgraded clutch or torque converter: $300–$800 if the transmission cannot handle the extra torque.
  • Fuel system improvements: $100–$400 (new fuel pump, lines, carburetor tuning or EFI conversion).
  • Exhaust system modifications: $300–$1,000 (headers, catalytic converter, muffler upgrades).
  • Accessories (alternator, power steering pump, A/C bracket): $200–$600 if reusing or replacing worn components.

Total investment can range from approximately $7,000 for a budget HO swap on a late‑model Chevy Silverado to $12,000 or more for a Fast Burn installation with full EFI and custom tuning on a classic Camaro. Despite the upfront cost, a crate engine often saves money compared to a full professional rebuild of an old engine — especially if the original block needs machining, new pistons, or cylinder head work.

Installation Guide: Step‑by‑Step Preparation and Execution

Installing a GM Performance 350 crate engine is a rewarding project that can be completed in a weekend with the right tools and workspace. The following steps are a high‑level guide; always consult the engine’s installation manual and your vehicle’s service manual for torque specs and specific procedures.

Pre‑Installation Preparation

  1. Choose a clean, well‑ventilated workspace. An engine hoist, engine stand, socket set, torque wrench, and a helper are essential.
  2. Remove the old engine. Drain all fluids, disconnect battery, remove the transmission (or support it), and lift the engine out. Label all vacuum lines, wiring, and bolts.
  3. Inspect the engine bay. Clean any debris, corrosion, or oil residue. Check motor mount brackets — many require the old metal brackets to be reused or replaced with aftermarket units.

Engine Preparation

  1. Prime the oil system. Before installation, use a priming tool on the distributor drive to pressurize the oil system. This prevents dry‑start damage.
  2. Install the flywheel or flexplate. Use new bolts (GM recommends Grade 8) and a thread locker. Torque to factory spec — typically 60–70 lb-ft.
  3. Attach the torque converter (if automatic). Ensure it is fully seated into the transmission pump before mating the engine.
  4. Mount the engine to the hoist and lower it into the engine bay. Align the transmission bellhousing, and slowly lower while guiding the motor mount studs into the frame brackets.

Final Installation Steps

  1. Tighten motor mounts and bellhousing bolts. Do not over‑torque aluminum transmission cases.
  2. Connect the transmission crossmember, then install the starter. Check that the starter engages the flexplate teeth without binding.
  3. Attach the alternator, power steering pump, A/C compressor, and other accessories. Use the correct belts and adjust tension.
  4. Install the intake and exhaust systems. Use new gaskets and properly torque intake manifold bolts in sequence.
  5. Connect fuel lines, vacuum lines, and wiring. For carbureted engines, verify fuel pressure (typically 5–7 PSI). For EFI (Ram Jet), follow the provided harness and ECM instructions.
  6. Fill the cooling system with distilled water or proper coolant. Bleed air from the block using the temperature sensor port.

First Start and Break‑In

  • Check oil level and prime the carburetor or prime the EFI system.
  • Start the engine and immediately check for oil pressure. If no pressure within 10 seconds, shut off and investigate.
  • Once running, set initial timing to 10–12 degrees BTDC (base) and adjust as needed.
  • Follow the break‑in procedure: vary engine speed between 1,500 and 2,500 rpm for the first 20 minutes. Avoid prolonged idle during break‑in.
  • After 500 miles, change the oil and filter. Inspect for leaks or metal debris.

Upgrading Supporting Systems for Maximum Reliability

A crate engine is only as good as the systems that support it. To fully realize the performance potential and ensure long‑term durability, consider these upgrades:

Cooling System

A higher‑output 350 generates more heat. Stock radiators in older vehicles are often undersized. Upgrade to a three‑row or aluminum crossflow radiator, and use a high‑flow water pump. Electric fans with a shroud improve airflow at idle and low speeds.

Exhaust System

Restrictive exhaust manifolds cost horsepower. Swap to ceramic‑coated headers (1⅝‑inch primary tubes for street applications, 1¾‑inch for high‑rpm builds). Pair with dual 2½‑inch or 3‑inch exhaust pipes and low‑restriction mufflers to reduce backpressure.

Fuel System

Carbureted engines: Replace the mechanical fuel pump with a high‑volume unit (rated for 110 GPH or more) and use a pressure regulator. EFI engines: Ensure the in‑tank pump delivers at least 40 PSI at load. Consider upgrading fuel lines to ⅜‑inch or AN‑6.

Ignition System

The stock HEI distributor works well, but a high‑energy performance coil and module (e.g., MSD Blaster) provide a more consistent spark. Set total timing to 34‑36 degrees for best power with modern fuels.

Common Questions and Myths About the 350 Crate Engine

Even experienced builders sometimes operate on outdated information. Here are clarifications to common points of confusion.

Myth: “A crate engine requires premium fuel and is not reliable for daily driving.”
Fact: Most GM Performance 350 crate engines are designed to run on 92‑octane pump gas. The 290‑hp version even tolerates 89 octane. Daily driving is perfectly feasible with proper tuning and maintenance — many owners log 100,000 miles with no issues.

Myth: “I can just drop the engine in without changing anything else.”
Fact: While the engine physically fits, the transmission, cooling, and fuel systems must be matched to the new power level. Failing to upgrade a weak transmission will result in early failure. Always consult GM Performance Parts documentation for compatible components.

Question: “Should I buy a long‑block or a turn‑key crate?”
A long‑block (short block plus cylinder heads) saves money but requires you to source the intake, carburetor, and accessories. A turn‑key crate comes fully assembled and ready to run — the recommended choice for first‑timers.

Question: “Can I install a 350 crate in a modern car with OBD‑II?”
Yes, but you will need aftermarket engine management (e.g., Holley Terminator, FAST) or use the Ram Jet EFI version which includes its own ECU. Expect to disable or simulate certain factory modules to avoid diagnostic trouble codes.

Final Thoughts

Upgrading to a GM Performance Parts 350 crate engine is one of the most satisfying and cost‑effective ways to breathe new life into a classic car, truck, or even a late‑model project. The combination of proven small‑block architecture, modern metallurgy, and factory quality control gives you dependable horsepower that can be enjoyed on the street, strip, or trail. By carefully selecting the right variant, budgeting for all supporting systems, and following a disciplined installation process, you can ensure that your 350 crate engine delivers decades of thrilling performance. Whether you are restoring a beloved muscle car or building a new hot rod from scratch, the small‑block 350 remains the quintessential choice for American V8 performance.