How accurate is Plastigage for measuring bearing clearance?
Documented on the Chevrolet Small Block 350 (sbc 350) build
Published March 28, 2026
Plastigage is accurate enough for quick checks and verification during assembly; it gives a reliable ballpark measurement.
Full Answer
Plastigage is accurate enough for quick checks and verification during assembly; it gives a reliable ballpark measurement. For precision work or final verification, use micrometers and bore/dial gauges to calculate clearance from measured diameters.
Documented In This Build
Related Knowledge
What is the acceptable rod bearing clearance for a Small Block Chevy 350?What causes a rod bearing clearance to be too tight?If clearance is out of spec, what are my options?Can I reuse the Plastigage after one measurement?How important is degreeing the cam?What torque sequence and values should I use for SBC heads?How do I set lifter preload or hydraulic lash?What should I do to prepare the engine for first start and break-in?
Related Parts
Rod bearing set (std/undersize as needed)
$60
Assembly lube
$8
Crankshaft (replacement or reman) / Crank grinding (if required)
$400
Related Tools
Torque wrench
Socket set and ratchet
Engine stand (engine removed from vehicle)
PlastigagePlastigage
Dial micrometer / outside micrometer
Dial bore gauge or telescoping gauge
Related Videos
Small Block Chevy 350 Build Pt. 6 | This Is How It's Actually Supposed To Be Done
Small Block Chevy 350 Build Pt.3 | Filing rings and checking main clearances
Small Block Chevy 350 Build Pt.5 | Continued frustrations with rod clearances
Small Block Chevy 350 Build Pt. 11 | Installing the intake manifold and figuring out sbc nuisances
Small Block Chevy 350 Build Pt. 7 | Checking Crank Clearance and installing the rods.
Small Block Chevy 350 Build Pt. 8 | Installing Camshaft and timing components