DynoCams 335 vs 400 TSB
Engine output on a stand — there is no drivetrain and no chassis in these numbers, which is the same basis Harbor Freight rates the engine on. Simulated at 800 ft and 75°F; thinner air makes less power and wants less fuel, so both the horsepower and the jet move with them. Governor removed. Compression 9.06:1.
Where each one wins
| RPM | DynoCams 335 | DynoCams 400 TSB | diff |
|---|---|---|---|
| 1500 | 2.83 | 2.85 | +0.03 |
| 2000 | 3.88 | 3.91 | +0.03 |
| 2500 | 4.99 | 5.02 | +0.04 |
| 3000 | 6.13 | 6.17 | +0.04 |
| 3500 | 7.36 | 7.35 | -0.00 |
| 4000 | 8.73 | 8.71 | -0.02 |
| 4500 | 10.19 | 10.15 | -0.04 |
| 5000 | 11.72 | 11.66 | -0.06 |
| 5500 | 13.29 | 13.23 | -0.06 |
| 6000 | 14.17 | 14.65 | +0.48 |
Horsepower at each rpm. Everything except the part named is identical between the two runs.
The top of the naturally aspirated cam ladder. At this level the camshaft is no longer the cheap part of the build — the springs, retainers and valvetrain it demands cost more than the cam does.
The bigger grind wins, but look at the rpm it wins at and ask honestly whether your clutch, gearing and nerve go there. A 212 turning this hard is a race engine with a maintenance schedule.
The 400 is Hemi and Ghost only. Fitting it to a non-Hemi head is not a tuning decision, it is a clearance problem.
The build
| Engine | Predator 212 Hemi (Gen 2) — 27/25mm valves · 5.5mm stems |
|---|---|
| Governor | Governor removed (full rev range) |
| Piston | Stock flat top — Hemi OEM (ARC DJ-1285PH · .550" CH) |
| Head | Stock Hemi head — as-cast factory |
| Head gasket | Stock HEMI — fiber .045" (ARC DJ-1310TP) |
| Camshaft | DynoCams 335 — .334" · 259.8/264.7 @.050 · 36 lb · 8,500-9,000 rpm |
| Valve springs | 34-36 lb open/race |
| Retainers | Billet w/ keepers, 36 lb — ARC DJ-1046 ($11.00) |
| Valves | Stainless kit, Hemi 27/25mm — GPS KDVALKIT27-25 · ARC DJ-SSVALVE HKT |
| Rocker arms | Stock rocker arm — 1:1 ratio |
| Connecting rod | ARC 6256 Billet — Hemi (+.020" raises CR) |
| Flywheel | ARC 6696 Billet — Hemi Speedway (32° BTDC) |
| Ignition coil | ARC rev limiter coil — 9,000 rpm |
| Carburetor | Nibbi PWK24 — 24mm flat slide |
| Air filter | Pod / cone filter — GPS / OMB angled filter kit |
| Exhaust | DynoCams race exhaust pipe |
| Fuel | Pump 87 octane |
The other one
| Engine | Predator 212 Hemi (Gen 2) — 27/25mm valves · 5.5mm stems |
|---|---|
| Governor | Governor removed (full rev range) |
| Piston | Stock flat top — Hemi OEM (ARC DJ-1285PH · .550" CH) |
| Head | Stock Hemi head — as-cast factory |
| Head gasket | Stock HEMI — fiber .045" (ARC DJ-1310TP) |
| Camshaft | DynoCams 400 TSB — .3997" · 267.1/272.4 @.050 · ⚠ HEMI / Ghost / 196 clone only, not Non-Hemi |
| Valve springs | 40 lb dual springs race head |
| Retainers | Billet w/ keepers, 36 lb — ARC DJ-1046 ($11.00) |
| Valves | Stainless kit, Hemi 27/25mm — GPS KDVALKIT27-25 · ARC DJ-SSVALVE HKT |
| Rocker arms | Stock rocker arm — 1:1 ratio |
| Connecting rod | ARC 6256 Billet — Hemi (+.020" raises CR) |
| Flywheel | ARC 6696 Billet — Hemi Speedway (32° BTDC) |
| Ignition coil | ARC rev limiter coil — 9,000 rpm |
| Carburetor | Nibbi PWK24 — 24mm flat slide |
| Air filter | Pod / cone filter — GPS / OMB angled filter kit |
| Exhaust | DynoCams race exhaust pipe |
| Fuel | Pump 87 octane |