How does Plastigauge work and is it accurate enough?
Documented on the Chevrolet Small Block 350 (sbc 350) build
Published March 28, 2026
Plastigauge is a quick, accurate method to check oil clearance by flattening a calibrated strip between the bearing and journal.
Full Answer
Plastigauge is a quick, accurate method to check oil clearance by flattening a calibrated strip between the bearing and journal. It is widely used for assembly checks; however, for final precision measurements, micrometers and bore gauges can verify journal and bearing dimensions.
Documented In This Build
Related Knowledge
What bearing clearance should I aim for on a Small Block Chevy 350?Can I reuse the existing rod bolts?What torque should I use for rod bolts?What should I do if a measured clearance is out of spec?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
Connecting rod set (matched)
Aftermarket / stock replacement$350
Rod bearing set (standard size)
King / Clevite / Generic$60
Rod bolts (ARP 2000 style)
ARP$120
Assembly lube
Lucas / ARP / Aeroshell$12
Plastigauge pack
Plastigauge$8
Related Tools
Socket set and ratchetGeneric
Engine standGeneric
Torque wrenchGeneric / Tekton 3/8" drive, 10-80 ft-lb
PlastigaugePlastigauge Standard
Feeler gauges / dial caliperMitutoyo / Craftsman (example)
Small brush or finger stick for assembly lube
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. 8 | Installing Camshaft and timing components
Small Block Chevy 350 Build Pt.1 | Lifting This Engine Without Breaking It