| Maker | Jacobs L-5MA7 | Jacobs L-6 | Jacobs L-6M | Jacobs L-6MB | Jacobs L-6MA | Jacobs L-4 | Jacobs L-4M |
| Arrangement | Radial | Radial | Radial | Radial | Radial | Radial | Radial |
| Cooling | Air | Air | >Air | Air | Air | Air | Air |
| No of Cyls | 7 | 7 | 7 | 7 | 7 | 7 | 7 |
| Bore/Stroke | 5.5" x 5.0" | 5.5" x 5.5" | 5.5" x 5.5" | 5.5" x 5.5" | 5.5" x 5.5" | 5.25" x 5.0" | 5.25" x 5.0" |
| Displacement | 831 cu ins | 914 cu ins | 914 cu ins | 914 cu ins | 914 cu ins | 757 cu ins | 757 cu ins |
| Comp Ratio | 6.0:1 | 6.0:1 | 6.0:1 | 6.0:1 | 6.0:1 | 5.38:1 | 5.38:1 |
| bmep Cruise | 105 | 100 | 96 | 96 | 96 | 97 | 97 |
| Blower ratio | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| 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 | 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 | 235 | 300 | 300 | 300 | 300 | 225 | 225 |
| @ RPM | 2100 | 2100 | 2100 | 2100 | 2100 | 2000 | 2000 |
| @ Altitude | 3700ft | 3700ft | 3700ft | 3700ft | 3700ft | Sea Level | Sea Level |
| HP Take-Off | 330 | 330 | 330 | 330 | 330 | 245 | 245 |
| @ RPM | 2125 | 2200 | 2200 | 2200 | 2200 | 2200 | 2200 |
| HP Cruise | 210 | 220 | 210 | 210 | 210 | 175 | 175 |
| @ RPM | 1900 | 1900 | 1900 | 1900 | 1900 | 1900 | 1900 |
| Fuel Octane | 73 | 80 | 80 | 80 | 80 | 73 | 73 |
| Prop Drive | Direct | Direct | Direct | Direct | Direct | Direct | Direct |
| Dry Weight | 510lbs | 535lbs | 550lbs | 550lbs | 550lbs | 480lbs | 473lbs |
| lb/Cruise HP | 2.43 | 2.43 | 2.62 | 2.62 | 2.62 | 2.74 | 2.70 |
| Carb(s) | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg | 1x Stromberg |
| Ignition | Scintilla Mag | Scintilla Mag | Scintilla mag | Scintilla Batt/Mag | Scintilla Mag | Scintilla Batt | Scintilla Mag |
| Electric Starter | Eclipse | Eclipse | Eclipse | Eclipse | Eclipse | Eclipse | Eclipse |
| Length | 19" | 19.875" | 19.875" | 19.875" | 19.875" | 19.00" | 19.00" |
| Height | 43.50" | 45.375" | 43.375" | 43.375" | 43.375" | 43.50" | 43.50" |
| Width | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Ht above bed | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
| Mount Dia | 16.50" | 16.50" | 16.50" | 16.50" | 16.50" | 16.50" | 16.50" |
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.