Walter Mikron I4               60      135     
Continental O-200             100      188     
Lycoming O-235 O4             100      207     
Franklin 225                  100      228     
Lycoming O-290-A O4           125      244     
Continental O-300             145      277     
Lycoming O-320                150      272     
Franklin 335                  150      365     0.41
Lycoming O-360                180      282     0.64
Avia (Czech) M-337 I6         210      326     0.64
Continental R-670             210      430     0.49
Franklin 6A8-215-B8F O6       215      485     0.44
Lycoming GO-435-A O6          240      364     0.66
Lycoming O-540                250      396     0.63
Continental Tiara GO-406      285      382     0.75
Continental O-520             325      380     0.86
Lycoming GO-480-A1A6          340      492     0.69
Continental GSO-526           340      540     0.63
Lycoming GSO-580-C            375      560     0.67
P & W R985 R9                 450      653     0.69
Lycoming O-720                520      597     0.87
                                                                              
Rotax 503                 50     85      
Great Plains VW 1600CC    55     160     
Hirth F23-EP2             60     70      
Jabira                    60     119     
PZL 2A-120                60     129     
Rotax 582                 63     95     Includes 20 lbs radiator, etc.
Continental A-65          65     173     
Limbach L 1800            66     154     
Limbach L 1700            66     161  
Rotax 618                 74     136     Includes 20 lbs radiator, etc.
Great Plains VW 2180CC    75     165     
Franklin 225              75     230     
Limbach L 2000            80     155     
Rotax 912                 80     165     Includes 20 lbs radiator, et
Continental C-85          85     207       
Limbach L 2400            94     181  
Continental C-90          95     207       
Great Plains VW 2600CC    96     190    
Stratus Subaru EA-81      100    205       
Continental O-200         100    220     
CAM-100                   100    225    Includes 20 lbs radiator, etc
Formula Power C100        104    210     
Rotax 914                 115    155     
Lycoming O-235            115    215     
PZL 4A-235                116    226     
Hirth F30-FP24            120    101     
Continental IO-240        125    250     
Continental O-300         145    277     
Lycoming O-320-A          150    243     
Lycoming O-320-D          160    253     
Franklin 335              165    320     
Formula Power F170        174    270
Lycoming O-360-A          180    265
Lycoming IO-360-A         200    293
NW Aero Ford V6           200    415
PZL 6A-350                205    330
Continental IO-360        210    350
NW Aero Chevy V6          230    420
Lycoming O-540-B          235    366
Lycoming O-540-E          260    368
Formula Power F260        274    390
Lycoming IO-540-K         300    443
Continental IO-520        300    459
Lycoming IO-720           400    568


Here are some certified engine weights. Thanks to Dirk Rackley at 
Vortec for obtaining this data.

    Engine       Horsepower   Weight   Ratio
    O-200-A           100      190     0.53
    O-200-B           100      190     0.53
    O-300-A           145      268     0.54
    O-300-E           145      268     0.54
    IO-346            165      297     0.56
    IO-360-B          210      327     0.64
    TSIO-360-A        210      334     0.63
    O-470-J           225      381     0.59
    O-470-R           230      438     0.53
    O-470-13          225      414     0.54
    O-470-15          190      405     0.47
    IO-470-C          250      432     0.58
    IO-470-D          260      426     0.61
    IO-470-E          260      461     0.56
    IO-470-F          260      464     0.56
    IO-470-V          260      472     0.55
    TSIO-470-D        260      511     0.51
    IO-520-L          285      466     0.61
    O-200-A           100      190     0.53
    O-200-B           100      220     0.45
    O-300-A           145      268     0.54
    O-300-E           145      268     0.54
    IO-346            165      297     0.56
    IO-360-B          210      327     0.64
    TSIO-360-A        210      334     0.63
    O-470-J           225      381     0.59
    O-470-R           230      438     0.53
    O-470-13          225      414     0.54
    O-470-15          190      405     0.47
    IO-470-C          250      432     0.58
    IO-470-D          260      426     0.61
    IO-470-E          260      461     0.56
    IO-470-F          260      464     0.56
    IO-470-V          260      472     0.55
    TSIO-470-D        260      511     0.51
    IO-520-L          285      466     0.61

    O-235-C1B           115      240     0.48
    O-290-D2C           140      263     0.53
    O-320-A2B           150      272     0.55
    O-320-A2C           150      271     0.55
    O-320-B2C           160      277     0.58
    O-320-D2A           160      277     0.58
    O-320-E2A           160      277     0.58
    IO-320-B1A          160      285     0.56
    IO-320-C1A          160      294     0.54
    IO-320-E2A          150      280     0.54
    O-360-A1D           180      284     0.63
    O-360-A3A           180      285     0.63
    IO-360-A1A          200      320     0.63
    IO-360-B1B          180      295     0.61
    IMO-360-B1B         225      274     0.82
    GO-480-B1D          270      432     0.63
    GO-480-G1D6         295      437     0.68
    IGO-480-A1B6        295      469     0.63
    IGSO-480-A1F6       340      498     0.68
    O-540-A1A5          250      396     0.63
    O-540-B2B5          235      395     0.59
    O-540-B4B5          235      395     0.59
    O-540-B4B5          260      398     0.65
    IO-540-A1A5         290      437     0.66
    IO-540-C4B5         250      402     0.62
    IO-540-D4A5         260      402     0.65
    IO-540-E1A5         290      437     0.66
    IO-540-G1A5         290      443     0.65
    IO-540-J4A5         250      409     0.61
    IO-540-K1A5         300      470     0.64
    AEIO-540-L1B5D      300      476     0.63
    IGO-540-B1C         350      500     0.70
    IGSO-540-A1D        380      530     0.72
    IGSO-540-B1A        380      532     0.71
    TIO-540-A1A         310      535     0.58
    TIO-541-E1A6        380      632     0.60
    TIOGO-541-A1A       400      663     0.60
    IO-720-A1A          400      597     0.67




    Engine       Horsepower   Weight 
   -----------------------------------
    O-200-A           100      190   
    O-200-B           100      190   
    O-300-A           145      268  
    O-300-E           145      268    
    IO-346            165      297 
    IO-360-B          210      327    
    TSIO-360-A        210      334    
    O-470-J           225      381    
    O-470-R           230      438    
    O-470-13          225      414    
    O-470-15          190      405   
    IO-470-C          250      432
    IO-470-D          260      426   
    IO-470-E          260      461   
    IO-470-F          260      464  
    IO-470-V          260      472   
    TSIO-470-D        260      511  
    IO-520-L          285      466   
    O-200-A           100      190 
    O-200-B           100      220 
    O-300-A           145      268   
    O-300-E           145      268 
    IO-346            165      297    
    IO-360-B          210      327   
    TSIO-360-A        210      334   
    O-470-J           225      381  
    O-470-R           230      438   
    O-470-13          225      414    
    O-470-15          190      405    
    IO-470-C          250      432   
    IO-470-D          260      426   
    IO-470-E          260      461   
    IO-470-F          260      464   
    IO-470-V          260      472  
    TSIO-470-D        260      511
    IO-520-L          285      466
    O-235-C1B         115      240    
    O-290-D2C         140      263    
    O-320-A2B         150      272    
    O-320-A2C         150      271   
    O-320-B2C         160      277   
    O-320-D2A         160      277  
    O-320-E2A         160      277  
    IO-320-B1A        160      285  
    IO-320-C1A        160      294  
    IO-320-E2A        150      280
    O-360-A1D         180      284
    O-360-A3A         180      285
    IO-360-A1A        200      320
    IO-360-B1B        180      295  
    IMO-360-B1B       225      274 
    GO-480-B1D        270      432   
    GO-480-G1D6       295      437   
    IGO-480-A1B6      295      469   
    IGSO-480-A1F6     340      498  
    O-540-A1A5        250      396   
    O-540-B2B5        235      395  
    O-540-B4B5        235      395   
    O-540-B4B5        260      398  
    IO-540-A1A5       290      437   
    IO-540-C4B5       250      402  
    IO-540-D4A5       260      402 
    IO-540-E1A5       290      437     
    IO-540-G1A5       290      443
    IO-540-J4A5       250      409  
    IO-540-K1A5       300      470  
    AEIO-540-L1B5D    300      476  
    IGO-540-B1C       350      500   
    IGSO-540-A1D      380      530  
    IGSO-540-B1A      380      532   
    TIO-540-A1A       310      535   
    TIO-541-E1A6      380      632  
    TIOGO-541-A1A     400      663   
    IO-720-A1A        400      597