Predator 212 Hemi vs Non-Hemi
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 | Hemi (Gen 2) | Non-Hemi (Gen 1) | diff |
|---|---|---|---|
| 1500 | 2.42 | 2.51 | +0.09 |
| 2000 | 3.33 | 3.46 | +0.13 |
| 2500 | 4.28 | 4.45 | +0.17 |
| 3000 | 5.27 | 5.49 | +0.22 |
| 3500 | 6.33 | 6.61 | +0.27 |
| 4000 | 7.44 | 7.77 | +0.33 |
| 4500 | 8.60 | 8.99 | +0.39 |
| 5000 | 9.81 | 9.97 | +0.16 |
| 5500 | 10.26 | 6.49 | -3.78 |
Horsepower at each rpm. Everything except the part named is identical between the two runs.
The same build on both heads, so the only variable is the engine you happen to own. The Hemi runs larger valves; the Non-Hemi breathes a little less and revs a little less freely.
Check the valve cover before you buy anything. Hemi covers are cast aluminium in a rounded rectangle; Non-Hemi covers are stamped sheet metal in a shape closer to a stop sign. There is very little parts interchange between them beyond the valves.
Note that the spring kits differ by head as well. Buying the wrong one is the most common way this goes wrong, and it is an easy mistake because the part is described the same way.
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 | Stock cam — Hemi & Non-Hemi factory grind |
| Valve springs | 18 lb Hemi specific (OMB/GPS) |
| Retainers | Stock retainers — OEM (ARC DJ-1040) |
| Valves | Stock valves — OEM |
| 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 | Stock coil — factory (no rev limiter) |
| Carburetor | 22mm clone carb — GPS / OMB Stage kit carb |
| Air filter | Pod / cone filter — GPS / OMB angled filter kit |
| Exhaust | GPS header + screw-on muffler kit |
| Fuel | Pump 87 octane |
The other one
| Engine | Predator 212 Non-Hemi Gen 1 — 25/24mm 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 | Stock cam — Hemi & Non-Hemi factory grind |
| Valve springs | 18 lb Non-Hemi (OMB/GPS) |
| Retainers | Stock retainers — OEM (ARC DJ-1040) |
| Valves | Stock valves — OEM |
| 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 | Stock coil — factory (no rev limiter) |
| Carburetor | 22mm clone carb — GPS / OMB Stage kit carb |
| Air filter | Pod / cone filter — GPS / OMB angled filter kit |
| Exhaust | GPS header + screw-on muffler kit |
| Fuel | Pump 87 octane |