The FRP Tuning 422ci High Compression Stroker Kit is a 1,300 horsepower-capable rotating assembly for max-effort naturally aspirated 6.4L 392 HEMI builds. A 426ci option uses a 4.050" crank and 6.175" rod for even more displacement and compression.
Why It's Different
Most stroker kits use a 6.125" rod. The FRP 422 uses a 6.200" rod with a 4.000" stroke for a higher wrist-pin location and maximum stability at high RPM. The +7cc dome piston is friendly to stock Eagle (5.7L) and Apache (6.4L) chambers, so you can reach 13-15:1 compression depending on head gasket and head choice. Valve pockets are opened and deepened for valves up to 2.200" and the largest camshafts FRP manufactures - spin it past 8,000 RPM with confidence.
What's Included
- CP Carrillo FRP-specific .010" oversized high-compression stroker pistons, +7cc dome
- Callies 8CW crankshaft - 4.000" (422ci) or 4.050" (426ci) stroke
- Molnar forged power-adder H-beam connecting rods - 6.200" (422ci) or 6.175" (426ci) - with ARP 2000 bolts
- Optional: bearings, and bearings with balancing (choose above)
Specs
- 422ci: 4.000" stroke, 6.200" rod
- 426ci: 4.050" stroke, 6.175" rod
- Piston: .010" over, +7cc dome
- Compression: 13-15:1 depending on gasket/head
- Rated: 1,300 hp
Fitment
- 6.4L 392 HEMI-based naturally aspirated engine builds (block machining and professional assembly required)
Important: FRP recommends verifying piston-to-valve and piston-to-wall clearance before final assembly. Improper clearances void any claim. Professional installation by a qualified engine builder is strongly recommended.
FAQ
422 or 426?
The 426ci uses a longer 4.050" stroke crank with a 6.175" rod for more displacement and compression; the 422ci uses a 4.000" crank and 6.200" rod for a higher pin location.
Will it work with stock heads?
The +7cc dome is designed to be stock Eagle and Apache chamber friendly; verify piston-to-valve clearance for your cam and heads.
Questions or Build Help?
Call Max Redline / American Muscle Performance at 954-507-6261 or email Sales@americanmuscleperformance.net with your engine, power goal and planned mods. Need it installed? See our engine build & installation services in Pompano Beach, FL.
