How many hours to rebuild a Chevy 350?
Typically, a rebuild of a Chevy 350 requires tens of hours of labor. For a professional shop, expect roughly 20–60 hours, with longer times if extensive machine work or performance upgrades are involved; DIY projects can exceed 60 hours and occasionally reach 100 hours or more depending on scope and skill.
Rebuilding a Chevy 350 involves a sequence of careful steps—from teardown to break-in—that each add to the total time. This article breaks down what usually happens, what factors drive variation in the clock, and how to estimate hours based on the rebuild’s scope.
What a Chevy 350 rebuild typically includes
Below are the common stages a rebuild covers. Time for each step varies with engine condition, desired spec, and whether machine work is needed.
- Disassembly and cleaning of the engine, including removal of the intake, timing cover, heads, and accessories
- Initial inspection and measurement of critical components (block bore, mains, rod journals, piston clearance, cylinder walls, and head surfaces)
- Machining and preparation (if needed): cylinder boring/honing, deck resurfacing, head resurfacing, line honing or align honing, and cam bearing installation
- Parts selection and preparation: pistons, rings, bearings, gaskets, seals, timing set, oil pump, lifters, camshaft, valves, springs, and upgraded components if desired
- Cleaning and pre-assembly preparation of all parts to ensure proper fit and clearances
- Assembly: torqueing to spec, correct clearances, proper lubrication, and careful mating of rotating assembly
- Initial startup, break-in procedure, oil and filter changes, and engine tuning for optimal performance and longevity
The duration of each step depends on the engine’s condition, the quality of parts used, whether machining is required, and the builder’s experience and workflow. A straightforward, stock-spec rebuild will generally be faster than a high-performance build.
Time estimates by rebuild scope
To translate the rebuild into hours, shops often categorize work by scope. The ranges below reflect typical labor times for professional shops and serious DIY projects with reasonable tooling.
- Basic rebuild (no machine work, stock components, standard tolerances) — about 20–40 hours
- Moderate rebuild (replacing major components with some machine work like honing and head gasket work) — about 40–60 hours
- Full machine shop rebuild with performance upgrades (bore/hone, decking, cam selection, balancing) — about 60–100 hours
- High-performance or complete restoration (blueprinting, aftermarket heads, forced induction prep, meticulous balancing) — 100+ hours
These ranges are guides. Actual hours depend on the engine’s condition, the extent of machine work, the number of parts replaced, and the builder’s pace and tooling availability.
Summary
In short, a Chevy 350 rebuild is a multi-day project whose duration hinges on scope. A typical professional rebuild falls in the 20–60 hour range, with longer timelines for machine work, performance upgrades, or meticulous restorations. DIY projects can extend well beyond that, especially when learning curves and tooling setup come into play. Planning for contingencies, sourcing quality parts, and aligning with a trusted shop or mentor can help keep the process on schedule.
How much does it cost to rebuild a Chevy 5.7 engine?
It may be a cheaper option: A full engine rebuild costs about $2,500 to $4,000. Rebuilding may make sense if the damage is limited and the engine's core is still in good shape. But if the engine has widespread failure or high mileage, a replacement may offer more long-term reliability.
What year is the best Chevy 350 engine?
The best Chevy 350 engine is often considered to be the 1996-2000 Vortec 5.7L due to its significant improvements in performance and efficiency. This version features Vortec cylinder heads for better airflow and the more durable hydraulic roller camshaft. While earlier models were simpler, later ones like the Vortec offered a stronger block design (880 casting), which is ideal for high-performance builds.
This video explains the advantages of the Vortec 5.7L engine: 58sMyvintageiron7512YouTube · Mar 17, 2023
1996-2000 Vortec 5.7L
- Vortec cylinder heads: Significantly improved airflow and combustion efficiency, leading to better performance and fuel economy.
- Hydraulic roller camshaft: This provides greater durability and reduced wear on the valvetrain compared to older flat-tappet cams.
- Stronger block: Blocks with the "880" casting number were used during this time and are built for roller cams, making them a great foundation for building a high-performance engine.
Other notable years
- Early 1990s (with roller cam): These engines are also desirable because they came with a roller valvetrain, but some may lack a provision for a mechanical fuel pump.
- 1970 LT-1: For those seeking raw, early-era power, the 1970 LT-1 version is a legendary, high-performance option with solid lifters and high compression.
- 1986 and newer (one-piece rear main seal): Engines from 1986 and newer are equipped with a one-piece rear main seal, which is different from the two-piece seal found on older engines. This distinction is important when selecting a compatible flywheel or flexplate.
How long should a full engine rebuild take?
An engine rebuild can take anywhere from a few days to several weeks or even months, depending on the engine's complexity, the mechanic's experience, part availability, and whether unforeseen issues arise. A basic rebuild on a standard vehicle might take a week, while a more elaborate or performance engine could take longer, and projects involving part lead times and extensive machine work can take months.
Factors that influence the timeline
- Engine type and complexity: Simple engines on common vehicles are faster to rebuild, whereas more elaborate trucking or performance engines take longer.
- Mechanic's experience: An experienced mechanic can complete a rebuild faster than a beginner.
- Part availability: Lead times for ordering parts can significantly extend the process, sometimes pushing it into months.
- Condition of the parts: The time required can increase if the engine is in poor condition, requiring more extensive cleaning, and machine work.
- Unforeseen issues: Problems discovered during disassembly can add unexpected delays.
- Labor time: While the core work might be around 40 hours, factoring in shop backlog, a typical rebuild can take anywhere from a week to over a month in a professional setting.
Typical timelines
- A few days: A very basic "engine freshening" might be done in a few days if all parts are readily available, though this is often not a "full" rebuild.
- One week: This is often cited as a reasonable timeline for a basic engine in a general transportation vehicle if parts are in stock and there are no major issues.
- Several weeks: A typical professional rebuild that includes ordering parts and machine work is often in the 3–5 week range.
- Several months: If parts are on backorder or the project involves exotic or custom components, the entire process can take months.
Is it cheaper to rebuild or replace a 350?
Bottom Line on Engine Replacement
Replacing a car engine can be costly, but choosing a rebuilt or remanufactured engine is often more affordable than buying a new vehicle. Rebuilt engines are cheaper ($3,500-$6,000) and involve replacing only worn parts, but may have shorter lifespans.
