Chevy 350 Valve Lash Adjustment: Hydraulic and Solid Lifters
Chevy 350 valve adjustment guide covering zero lash, hydraulic preload, solid-lifter cam cards, firing-order method, and common mistakes.
Valve adjustment depends on lifter type. Chevrolet specifies 1/8 turn past zero lash for its hydraulic-flat-tappet 350/290 and 3/4 turn past zero lash for Ram Jet 350. COMP Cams describes an ideal hydraulic plunger preload of 0.030 ± 0.010 inch for its applicable lifters. Solid-lifter lash must come from the cam card, usually at the stated hot or cold condition.
Valve lash and hydraulic preload are not interchangeable terms. A solid lifter needs running clearance between parts; a hydraulic lifter needs its internal plunger positioned within its operating range after all free clearance is removed.
Before adjusting anything, identify the camshaft and lifter type. If the engine's parts history is unknown, remove a valve cover and investigate rather than assuming that every 350 uses the same number of turns.
Interactive valve-adjustment cycle
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Follow each cylinder in firing order and adjust only when that cylinder's lifters are on the cam's base circle.
Chevy 350 Valve Lash Adjustment
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| 350/290 hydraulic setting | 1/8 turn past zero lash | Chevrolet crate-engine specification |
| Ram Jet 350 hydraulic setting | 3/4 turn past zero lash | Chevrolet crate-engine specification |
| COMP hydraulic target | 0.030 ± 0.010 in preload | For applicable COMP lifters |
| Solid lifter | Use cam card | Hot/cold condition and intake/exhaust may differ |
Turns past zero lash are meaningful only when rocker-stud thread pitch and valvetrain parts match the procedure. Never apply a hydraulic-preload method to solid lifters.
How to use this specification correctly
- 01
Confirm hydraulic flat tappet, hydraulic roller, solid flat tappet, or solid roller lifters and obtain the cam or lifter instructions.
- 02
Remove the valve covers, disable ignition, and rotate the engine by hand in its normal direction.
- 03
Place cylinder 1 at compression TDC so both lifters are on the base circle.
- 04
For a hydraulic setup, gently remove free play while spinning or moving the pushrod; the point at which clearance disappears is zero lash, not final preload.
- 05
Turn the adjuster the specified amount past zero lash. For a solid setup, use the specified feeler gauge at the stated hot or cold condition.
- 06
Rotate the crank 90 degrees and move through the 1-8-4-3-6-5-7-2 firing order, adjusting both valves for each cylinder at compression TDC.
- 07
Recheck several positions, install the covers, and verify quiet operation, stable vacuum, and full cylinder contribution.
How to identify zero lash
Zero lash is the point where free clearance has just been removed while the lifter remains on the cam's base circle. Crushing the plunger while searching for resistance can create a false zero point. Use light finger pressure and repeat the check if uncertain.
Why the number of turns varies
- Rocker-stud thread pitch
- Available lifter plunger travel
- Cam and lifter manufacturer's preload target
- Pushrod length and valvetrain geometry
- Production versus aftermarket rocker system
Common adjustment mistakes
- Adjusting on the cam lobe instead of the base circle
- Confusing zero lash with zero preload
- Using hydraulic instructions on solid lifters
- Setting hot lash on a cold engine without the cam maker's correction
- Masking a bent pushrod or worn cam lobe with extra adjustment
Chevrolet 350 Small-Block (5.7L V8) 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 Valve Lash Adjustment: Hydraulic and Solid Lifters FAQs
How many turns past zero lash for a Chevy 350?+
It depends on the exact valvetrain. Chevrolet specifies 1/8 turn on the 350/290 example and 3/4 turn on Ram Jet 350, proving that one universal turn count is unsafe.
What is zero lash?+
Zero lash is the point where free clearance has just disappeared between the valvetrain parts while the lifter is on the cam base circle.
Can solid lifters be adjusted like hydraulic lifters?+
No. Solid lifters require a measured clearance from the cam card, usually specified for a hot or cold engine.
Can I adjust all Chevy 350 valves at TDC number 1?+
Some procedures adjust selected valves in two crank positions, but the firing-order method is easier to verify: adjust each cylinder when it is at compression TDC.
What happens with too much hydraulic preload?+
Excess preload can hold a valve off its seat, causing rough idle, low compression, low vacuum, misfire, or valve damage.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
1Chevrolet Performance 350/290 Long Block guide (P/N 19172591)Primary Chevrolet Performance guide for the pre-1986-style 350/290 long block.↗2Chevrolet Performance Ram Jet 350 guide (P/N 19417619)Primary Chevrolet Performance installation and calibration guide for Ram Jet 350 engines.↗3COMP Cams camshaft installation instructionsManufacturer instructions covering hydraulic preload and solid-lifter lash.↗