The size of the factory 426 Hemi rod journal size is a question which comes up often. Let’s examine what the 426 Hemi rod journal size is.
The 426 Hemi connecting rod journal diameter is 2.374″-2.375.” The rod bearing bore size or outside diameter of the rod bearing is 2.5000″-2.5005.”
This article will explain the journal measurements and sizes in more detail. In addition, it will include the factory allowable out-of-round, taper and crankshaft bearing clearances.
426 Hemi Rod Journal Size
Connecting rod bearings are small and it’s definitely not one of the first engine parts talked about. Although they are one of the most important engine parts.
When checking for bearing clearances or purchasing connecting rods, knowing the factory specifications are something people should know.
Let’s take a close look at the rod journal, bore, bearing sizes and Hemi rods.
Crankshaft: 426 Hemi Connecting Rod Journal Size
The connecting rod journal size is the diameter of the rod journal on the crankshaft. It’s what the big end of the rod bolts on to. A Hemi crankshaft has four of them, each one sharing two connecting rods each.
- The 426 Hemi rod bearing journal diameter is 2.374″-2.375″ (2.375″).
- The maximum allowable out-of-round is .0003″
- The maximum allowable taper is .0005″
426 Connecting Rods: Bearing Bore Diameter
The rod bore size is the inside diameter of the rod bearing housing without the bearings installed. It’s also the outside diameter of the rod bearing.
- The 426 Hemi rod bearing bore diameter is 2.5000″-2.5005″
Rods: Bearing Clearance
Two tools are required when checking the clearances on the connecting rod bearings:
- Micrometer to measure the rod bearing journals.
- A dial bore gauge to measure the inside diameter of the Hemi rod bearing.
The rod bearing journal diameter can be checked with a precision micrometer sized for the range of the journals you will measure.
There are many cheap micrometers out there for sale you should avoid. Use a quality micrometer that will measure down to the 0.0001-inch.
Also, the best dial bore gauges are accurate down to 0.0001-inch. The two tools can be purchased as a set offering measurements from the 2-4″ range.
The following table indicates the 426 Hemi rod bearing clearances for each year:
Rod Bearing Desired Clearance
Rod Bearing Maximum Clearance
- The Plymouth and Dodge service manuals indicate the correct rod bearing clearance is from .0015″ to .0025.”
Remember, higher performance engines require more bearing clearance than factory stock. The following video describes that plus bearing information.
If you’re interested in the main bearings journal size, bearings and clearances, check my article, 426 Main Bearing Size.
If you have any questions about rods, bearings, posts or more information you’d like to contribute, send us an email found specifically on our contact page.
For the past 40 years, I’ve been studying and researching Mopar engine specs, rods and bearings like the 426 Hemi. I’ve assembled engines, read books, articles, magazines, watched videos, attended seminars and spoken to other Mopar experts about the topic.
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