| Maker | Walter Atom | Walter Mikron | Walter Minor | Walter Junior | Walter Major 4 | Walter Major 6 | Walter Sagitta-IRC |
| Arrangement | Horizontal | Inline | Inline | Inline | Inline | Inline | V 60 Deg |
| Cooling | Air | Air | Air | Air | Air | Air | Air |
| No of Cyls | 2 | 4 | 4 | 4 | 4 | 6 | 12 |
| Bore/Stroke | 3.35" x 3.78" | 3.35" x 3.78" | 4.14" x 4.53" | 4.53" x 5.51" | 4.65" x 5.51" | 4.65" x 5.51" | 4.65" X 5.51" |
| Displacement | 67.1 cu ins | 133.0 cu ins | 244.0 cu ins | 354.8 cu ins | 373.6 cu ins | 561.2 cu ins | 1120.5 cu ins |
| Comp Ratio | 5.2:1 | 5.2:1 | 5.3:1 | 5.2:1 | 5.2:1 | 5.2:1 | 5.50:1 |
| bmep Cruise | 113 | 117 | 122 | 117 | 121 | 128 | 118 |
| Blower ratio | N/A | N/A | N/A | N/A | N/A | N/A | 7.55:1 |
| Cyl Material | Steel | Steel | Steel | Steel | Steel | Steel | Steel |
| Valves per cyl | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh |
| Valve Arr. | OHV | OHV | OHV | OHV | OHV | OHV | OHV |
| HP max - not Take-Off | 28 | 54 | 95 | 120 | 130 | 205 | 450 |
| @ RPM | 3000 | 2800 | 2550 | 2300 | 2350 | 2350 | 2600 |
| @ Altitude | Sea Level | Sea Level | Sea Level | Sea Level | Sea Level | Sea Level | 6562 ft |
| HP Take-Off | NA | 48 | 77 | NA | 120 | 190 | 430 |
| @ RPM | NA | 2300 | 2050 | NA | 2050 | 2050 | 2490 |
| HP Cruise | 25 | 50 | 85 | 105 | 120 | 190 | 400 |
| @ RPM | 2600 | 2550 | 2260 | 2000 | 2100 | 2100 | 2400 |
| Fuel Octane | 68 | 68 | 68 | 68 | 73 | 73 | 85 |
| Prop Drive | Direct | Direct | Direct | Direct | Direct | Direct | Geared |
| Dry Weight | 88.2 lbs | 132.3 lbs | 205 lbs | 297.6 lbs | 308.6 lbs | 385.8 lbs | 815.7 |
| lb/Cruise HP | 3.52 | 2.64 | 2.41 | 2.84 | 2.57 | 2.03 | 2.05 |
| Carb(s) | 2 X Amal | 1 X Claudel | 1 X Claudel | 1 X Claudel | 1 X Claudel | 2 X Claudel | 1 X Stromberg |
| Ignition | Bosch Mag(2) | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(2) |
| Electric Starter | N/A | Own H/C | Own H/C | Own H/C | Own H/C | Own H/E | H/E |
| Length | 20.08" | 31.65" | 44.09" | 46.46" | 46.46" | 59.84" | 70.36 |
| Height/O.D. | 16.10" | 25.00" | 24.80" | 30.19" | 30.19" | 31.58" | 30.75 |
| Width | 32.09" | 13.46" | 17.32" | 19.49" | 19.49" | 19.29 | 28.54 |
| Bed centres | N/A | 9.84" | 11.89" | 21.26" | 21.26" | 25.20" | 25.20 |
| Mount Dia | NA | NA | NA | NA | NA | NA | NA |
Let me know if any of the above does not read true, or if you have information that does not agree. Wherever possible, I will update these pages on a regular basis as data comes in.