Stock 19 lb/hr. Strokers need 24 lb/hr (Mopar 5.9 'yellow tops'). High-output strokers and supercharged setups need 30+.
Injector sizing scales with peak power demand. Approximate rule: HP / (cylinders * BSFC / 60 * duty cycle). For a 250 hp 4.6 stroker at 0.50 BSFC and 85% duty: ~22 lb/hr per cylinder. Stock 19 lb/hr maxes out around 215 hp.
Common upgrade paths:
The injector slope (lb/hr value the PCM uses to calculate fuel quantity from pulse width) lives in the PCM tune. With a stock 19 lb/hr slope and a physical 24 lb/hr injector, the engine runs ~25% rich. You need either a custom tune (HPTuners on 96+ trucks) or to find a PCM that already has 24 lb/hr slope (some 5.9 Magnum PCMs). Many stroker builders accept slightly off fuel trims and let the closed-loop O2 correction handle it, which works at cruise but not WOT.
If you can do only one fuel mod for a stroker, do the 24 lb/hr injectors. Pair with the Walbro 255 pump for headroom.
| Part | Vendor | Est. price |
|---|---|---|
| Mopar 24 lb/hr yellow top injectors (set 6) | Mopar | ~$240 |
| Bosch III 30 lb/hr injectors (set 6) | Bosch | ~$360 |
| Fuel injector o-ring kit | FelPro | ~$20 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.