| Maker | Lycoming O-145- A2 | Lycoming O-145- A3 | Lycoming O-145- B1 | Lycoming O-145- B2 | Lycoming O-145- B3 | Lycoming O-145- C1 | Lycoming O-145- C2 |
| Arrangement | Horizontal | Horizontal | Horizontal | Horizontal | Horizontal | Horizontal | Horiz. |
| Cooling | Air | Air | >Air | Air | Air | Air | Air |
| No of Cyls | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Bore/Stroke | 3.625" x 3.5" | 3.625" x 3.5" | 3.625" x 3.5" | 3.625" x 3.5" | 3.625" x 3.5" | 3.625" x 3.5" | 3.625" x 3.50" |
| Displacement | 144 cu ins | 144 cu ins | 144 cu ins | 144 cu ins | 144 cu ins | 144 cu ins | 144 cu ins |
| Comp Ratio | 5.65:1 | 5.65:1 | 6.50:1 | 6.50:1 | 6.50:1 | 6.50:1 | 6.50:1 |
| bmep Cruise | 110 | 110 | 112 | 112 | 112 | 108 | 108 |
| Blower ratio | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Cyl Material | Cast Semi-Steel | Cast Semi-Steel | Cast Semi-Steel | Cast Semi-Steel | Cast Semi-Steel | Cast Semi-Steel | Cast Semi-Steel |
| Valves per cyl | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh | 1 Inl 1 Exh |
| Valve Arr. | OHV | OHV | OHV | OHV | OHV | OHV | OHV |
| HP max - not Take-Off | 55 | 55 | 65 | 65 | 65 | 75 | 75 |
| @ RPM | 2300 | 2300 | 2550 | 2550 | 2550 | 3100 | 3100 |
| @ Altitude | Sea Level | Sea Level | Sea level | Sea Level | Sea Level | Sea Level | Sea Level |
| HP Take-Off | 55 | 55 | 65 | 65 | 65 | 75 | 75 |
| @ RPM | 2300 | 2300 | 2550 | 2550 | 2550 | 3100 | 3100 |
| HP Cruise | 42 | 42 | 47 | 47 | 47 | 55 | 55 |
| @ RPM | 2100 | 2100 | 2300 | 2300 | 2300 | 2800 | 2800 |
| Fuel Octane | 73 | 73 | 73 | 73 | 73 | 73 | 73 |
| Prop Drive | Direct | Direct | Direct | Direct | Direct | Direct | Direct |
| Dry Weight | 162lbs | 164lbs | 155lbs | 165lbs | 167lbs | 145lbs | 165lbs |
| lb/Cruise HP | 3.86 | 3.91 | 3.30 | 3.51 | 3.55 | 2.82 | 3.00 |
| Carb(s) | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg |
| Ignition | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(1) | Scintilla Mag(2) | Scintilla Mag(2) | Scintilla Mag(1) | Scintilla Mag(2) |
| Electric Starter | N/A | Eclipse | N/A | N/A | Eclipse | N/A | N/A |
| Length | 24.625" | 24.625" | 23.75" | 25.625" | 24.625" | 23.75" | 24.625" |
| Height/O.D. | 19.312" | 22.125" | 20.125" | 20.125" | 22.125" | 20.125" | 22.125" |
| Width | 29.562" | 29.562" | 29.562" | 29.562" | 29.562" | 29.562" | 29.562" |
| Ht above bed | 9.469" | 9.469" | 9.469" | 9.469" | 9.469" | 9.469" | 9.469" |
| Mount Dia | 10.25" | 10.25" | 10.25" | 10.25" | 10.25" | 10.25" | 10.25" |
Let me know if any of the above does not read true, or if you have other information that does not agree.
Wherever possible, I will update these pages on a regular basis as data comes in.