Chevy 350 Camshaft Installation Alignment Diagram
Chevy 350 cam timing dot-to-dot guide with crank mark at 12, cam mark at 6, flat-tappet preparation and degree-check cautions.
For a standard-position Gen I Chevy 350 timing set, install the crank sprocket mark at 12 o'clock and the cam sprocket mark at 6 o'clock so the two marks face each other. This dot-to-dot position phases the cam but is not automatically cylinder 1 compression TDC for distributor installation. Multi-keyway sets must use the exact keyway and matching timing symbol specified by the timing-set maker.
Cam timing determines when the valves move relative to piston position. On the Chevy 350 Gen I, being one tooth or one keyway wrong can produce poor compression, a no-start, or piston-to-valve contact. The marks must be identified on the actual sprockets before the chain is installed.
The traditional small-block uses two facing marks for standard installation. Replacement crank gears may include separate advance, retard and zero keyways, each paired with its own symbol.
The interactive diagram is a preparation and verification controller. Use the physical drawing supplied with the exact timing set for tooth-level placement, because multi-keyway crank gears, variable cam phasers and replacement sprockets can carry extra dots, triangles or part-number marks that are not timing references.
Interactive Chevy 350 Gen I cam-timing workflow
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Follow the installation stages in order. The clock positions describe the front-facing sprocket marks, not ignition timing at the harmonic balancer.
Chevy 350 Camshaft Installation Alignment Diagram
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| Crank mark | 12 o'clock | Faces cam sprocket |
| Cam mark | 6 o'clock | Faces crank sprocket |
| Relationship | Dot to dot | Standard-position keyway |
| Final authority | Timing-set sheet + cam card | Multi-keyway and aftermarket builds |
Clean dot-to-dot alignment is only the beginning: verify cam end play, lifter compatibility, lobe lubrication, piston-to-valve clearance and the cam card's installed centerline.
How to use this specification correctly
- 01
Confirm engine code, model year, camshaft, timing cover and timing-set part number. Read the entire service or component procedure before rotating either shaft.
- 02
Disconnect the battery, drain fluids required by the vehicle procedure and support accessories safely. Keep dirt, gasket debris and coolant out of the oil pan and open engine.
- 03
Before chain removal, rotate the assembled engine to the source-specified timing position and photograph every mark, keyway and colored link. Do not rotate crank and cam independently on an interference engine.
- 04
Inspect the crank key, cam dowel or phaser locator, sprocket teeth, chain rollers, guides, tensioner, thrust plate and oiling passages. Replace damaged parts as a matched system.
- 05
Lubricate cam journals and lobes with the cam maker's assembly lubricant, protect the bearings and slide the cam in without striking a lobe against a bearing edge.
- 06
Place the selected crank-gear keyway on the crank key, arrange the cam dot at 6 and crank dot at 12, then install both sprockets and chain together without moving either shaft.
- 07
Apply only the specified lubricant and thread treatment. Tighten the sprocket fasteners with the documented holding method; never use the timing chain itself as a counterhold.
- 08
Release or install the tensioner exactly as directed, then rotate the crankshaft slowly by hand through at least two complete revolutions. Stop immediately if resistance rises unexpectedly.
- 09
Return to the verification position and confirm sprocket marks, mechanical clearance and cam end play. Colored chain links may not return to the marks after only two crank revolutions, so judge the final check by the manual's sprocket-mark rule.
- 10
Prime the oiling system when required, reinstall covers and the correct balancer/pointer combination, then verify oil pressure and ignition/cam correlation after startup.
Which timing marks apply
The traditional small-block uses two facing marks for standard installation. Replacement crank gears may include separate advance, retard and zero keyways, each paired with its own symbol.
Chevrolet's 350/290 is a flat-tappet example; its lobe/lifter preparation and break-in are as important as mark alignment. Roller conversions follow their own cam, thrust and retainer instructions.
Installation and verification method
Lubricate cam journals and lobes with the cam maker's assembly lubricant, protect the bearings and slide the cam in without striking a lobe against a bearing edge.
Place the selected crank-gear keyway on the crank key, arrange the cam dot at 6 and crank dot at 12, then install both sprockets and chain together without moving either shaft.
Critical mistakes to avoid
- Choosing the wrong multi-keyway symbol
- Assuming dot-to-dot equals No.1 compression TDC
- Forcing the cam through a bearing
- Failing to check piston-to-valve clearance
- Starting a flat-tappet cam without the prescribed break-in
Cam timing is not ignition timing
Sprocket marks phase the camshaft to the crankshaft. A balancer and pointer are used later to set or verify ignition timing. Aligning chain dots does not establish the distributor's No. 1 terminal or program an ECU cam offset.
On a four-stroke engine the crank rotates twice for one cam revolution. A dot-over-dot chain-installation position may place cylinder 1 on overlap rather than its firing stroke; identify compression TDC separately before installing a distributor or routing ignition wires.
Pre-start checklist
- Correct keyway and timing symbols selected
- Cam dowel/phaser slot fully engaged
- Chain tight on the drive side as specified
- Guides and tensioner installed and released
- Fasteners torqued with correct thread treatment
- Cam end play/clearance checked
- Two slow crank revolutions completed
- Sprocket marks rechecked at verification position
- Oil system primed where required
Chevrolet Chevy 350 Gen I specifications can change by model year, engine, platform, wheel, and installed component. Confirm the VIN or engine identity, part numbers, fastener condition, and the current manufacturer instructions before service.
Chevy 350 Camshaft Installation Alignment Diagram FAQs
Where do Chevy 350 timing dots point?+
For standard installation, the crank dot points up at 12 o'clock and the cam dot points down at 6 o'clock.
Is dot-to-dot No.1 compression TDC?+
Do not assume that. The crank is at TDC, but identify No.1 compression separately before installing the distributor.
Should the colored chain links line up again after two rotations?+
Not necessarily. Link-tooth counts determine when colored links repeat. After hand rotation, use the sprocket alignment and verification procedure stated by the service manual.
Can the crankshaft be turned with the timing chain removed?+
Do not do so unless the exact service procedure places the pistons safely and explicitly permits it. GM and Mopar procedures warn of piston-to-valve damage.
Should an aftermarket cam be degreed?+
Yes when its manufacturer or the engine build requires it. Dot alignment establishes the selected keyway position; degree-wheel measurement verifies the cam's actual installed centerline.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
1Crane Cams camshaft installation instructionsThe camshaft maker illustrates the Chevrolet small-block dot-over-dot installation and requires end-play, lubrication and clearance checks.↗2Chevrolet Performance 350/290 engine guideChevrolet identifies the named 350's flat-tappet camshaft, firing order and break-in requirements.↗