L = Medium Duty V8 272 8.3:1 Comp ratio, 2 bbl, Gov=Velocity, Dist Dual advance.
C = Medium duty V8 292 7.9:1 Comp ratio, 2 bbl, Gov=Velocity, Dist Dual advance.
U = Heavy Duty V8 272 7.6:1 Comp ratio, 4 bbl, Gov =Vacuum, Dist Loadomatic.
D = Heavy Duty V8 292 7.6:1 Comp ratio, 4 bbl, Gov=Vacuum, Dist Centrifugal Adv.
N = Heavy Duty V8 302 7.5:1 Comp ratio, 4 bbl, Gov = Vacuum, Dist Centrifugal Adv.
F = Heavy duty V8 332 7.5:1 comp ratio, 4 bbl, Gov Vacuum, Dist centrifugal adv.
This is according to my 58 shop manual so the C was a 292.
What strikes me funny is the medium duty 272 L code having a higher Comp ratio than the 292 C code medium duty, must have had smaller combustion chamber heads.

55 Vicky & customline
58 Rack Dump, 55 F350 yard truck, 57 F100
59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?