Product Description
Cummins 3920779 — Cylinder Head Bolt (Short) for 5.9L 12-Valve
MPN: 3920779 | Also Known As: hex flange head cap screw, head bolt (short) | Used With: 3920780 (medium), 3920781 (long)
Why This Part
- ✓ OE fastener for proper clamping force and sealing on 5.9L 12-valve heads.
- ✓ Direct-fit replacement for factory “short” head bolt locations.
- ✓ Hardened OE metallurgy and flange head for repeatable torque.
- ✓ Ideal when refreshing the head gasket or replacing stretched/corroded bolts.
Quick Specs
| Type | Hex flange head cap screw / cylinder head bolt (short) |
|---|---|
| OE Part # | 3920779 |
| Set Composition | Typical 5.9L 12V uses 26 total bolts: 6 short (3920779), 14 medium (3920780), 6 long (3920781) |
| Qty Required | 6 pieces per engine for short positions (sold individually) |
Counts reflect common 12-valve layouts; always verify service manual and ESN.
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–1998 | 5.9L Cummins 12-Valve (6BT) | Dodge Ram 2500/3500 |
Industrial/Off-Highway: Also found on various 4B/6B platforms; confirm by ESN.
Often Paired With
- Head gasket: choose thickness per piston protrusion/spec
- Medium/long bolts: 3920780 (14x) & 3920781 (6x)
- ARP head studs: upgrade path in higher boost builds
- KDP repair kit: preventative timing cover “killer dowel pin” fix on 12V
What’s In The Box
- (1) Genuine Cummins Cylinder Head Bolt — Short (3920779)
- Other lengths/hardware sold separately.
Install Tips
- Chase threads and clean bolt holes; lightly oil threads and under-head per Cummins procedure.
- Follow the factory torque/angle sequence for 12-valve heads.
- Replace bolts if any show stretch, corrosion, or thread damage.
FAQ
HOW MANY OF THE 3920779 “SHORT” BOLTS DOES A 12-VALVE USE?Typically six short bolts per engine, alongside 14 medium (3920780) and six long (3920781), for 26 total. Verify your service manual.
WILL THIS FIT MY 1989–1998 5.9L 12-VALVE RAM?Yes—3920779 is used in the short positions on 5.9L 12-valve heads found in 1989–1998 Ram 2500/3500. Confirm by VIN/ESN if components have been changed.
IS THIS A GENUINE CUMMINS FASTENER?Yes—OE Cummins hex flange head cap screw for cylinder head applications.
CAN I MIX NEW BOLTS WITH OLD ONES?Best practice is to replace all 26 bolts during head service to maintain even clamping load.
SHOULD I UPGRADE TO STUDS?For stock power, factory bolts are fine. For higher boost/HP, ARP head studs provide superior clamping and reuse capability.
