Hi, depends on the length of gun, generally three lengths are commonly found ...Light / Ladies at around 39" long, only in .177 a good one will be around 600fps,
Standard length Lincoln's / B's / D's later 1919-39 C and S models. These can go up to 725 fps if fresh inside, again 99% are in .177
45" Guns...pre 1919 known as Sporting or at the end of production Standard model (.22 / .25) then again from 1919-39 as standard no2 (.22) or C.S. / Club Special / Club Standard (.177).
These long guns can be full power, with the earlier Sporting .22 normally making high 10's to full power and even slightly over (up to 600fps and beyond in .22!)
The 1919-39 45" .22 guns usually had a different piston / rod and these seem to top out at 560-70 I have found.
The 1919-39 45" .177 guns can go up to high 700's in fps.
I have omitted some rarer guns found, and been simplistic but the above is a basic guide. I have used FPS and these figures are using fairly light waisted pellets as would have been available originally.
Bear in mind these figures are for either little used, or rebuilt and run-in gins in good order, these guns are all getting older now, and although built to a very high standard originally, may have had generations of neglect and abuse, so always chrono/ test fire for accuracy any example you are intent on using to see how it shoots. They do vary and some which have had all sorts down the barrel may not be accurate.
ATB, Ed