How to make 550 hp from a 408 Cleveland stroker
408 cubes · CHI heads · pump gas if you are careful
Peak horsepower
585 hp @ 6600
Peak torque
518 lb-ft @ 5300
Displacement
402 ci
Compression
12.1:1
Engine dyno, as configured — flywheel horsepower. Standard test config: stock manifolds through 18" of pipe, air cleaner lid flipped, no accessories driven. Factory SAE net ratings are measured as‑installed and read 15–25% lower. Rev ceiling for this combination: 6600 rpm.
A 408 is the answer to almost every "can a 351 make X" question. Four inches of stroke, modern heads with the bowls blended, and a cam that would be peaky in 351 cubes suddenly pulls from down low.
Displacement is the cheapest torque there is. Compare this curve against the 500 hp non-stroker page — similar peak, completely different engine to drive.
The rods and the crank are where the money goes and where it should. At this output the bottom end is doing real work.
The build
| Block | Ford Performance BOSS 351 — 9.2" deck (~$2,650) |
|---|---|
| Crank | Eagle forged 4340 — 4.00" stroke / 408 ci (~$900) |
| Rods | H-beam 4340 forged (Eagle/Scat/Molnar) — to ~900 HP |
| Pistons | Auto Tec 1000520 forged 4032 flat 2V — 408 · 1.185" CH · −3cc · ~$718 |
| Head gasket | OEM compressed (.040") — neutral |
| Cylinder heads | CHI 3V 225cc — the modern Cleveland head |
| Porting | Bowl blend / pocket port |
| Camshaft | Howards 240/246 — hyd flat (CL231721-10 · .640"/.649") |
| Valve springs | COMP 26943-16 dual |
| Rocker arms | Full roller 1.73 — needle bearing |
| Intake manifold | Edelbrock RPM Air-Gap |
| Carburetor | Holley 850 cfm — strip |
| Exhaust | Long tube 1-3/4" — hot street |
| Ignition | MSD Pro Billet distributor + 6AL box — ~8,000 rpm |
| Fuel | Sunoco 260 GT Plus 104 — unleaded, 13% ethanol |
| Air cleaner | Stock air cleaner, LID FLIPPED — DYNO STANDARD |