Model                   Part Number     FreeLength  FittedLength    SpringRate      Identifyingpaint marks

Front
Spit-4 (Mk I)
from  FC 3,214 to
FC 39,527               210566          12.21"      7.42"           150 lbs/in      light blue
(Mk I)
post FC39,527           209685          12.59"      7.8"                150 lbs/in      green
Spit (Mk II)            209685          12.59"      7.8"                150 lbs/in      green
Spit (Mk III)           214144          12.21"      7.5"                150 lbs/in      purple
Spit (Mk IV)            214144          12.21"      7.5"                150 lbs/in      purple
Spit 1500               TKC1881         12.35"      8.0"                180 lbs/in      purple/white
GT6 MK I                212425          12.46"      8.06"               200 lbs/in      -
GT6 MK II               212425          12.46"      8.06"               200 lbs/in      -
GT6 MK III              212425          12.46"      8.06"               200 lbs/in      -

Back
Model               Part Number     Arch Height     Arch Height     Spring Rate.    Nr of leafs & style         Identifying paint marks
                                            Free                Fitted           lbs/in

Spit-4 Mk I     305894  -   -1.88"  166 lbf/in
at the wheel    fixed spring    -
Spit  Mk II     305894  -   -1.88"  166 lbf/in
at the wheel    7 leaves
.2188" thk.
fixed spring    -
Spit  Mk III    305894  -   -1.88"  166 lbf/in
at the wheel    7 leaves
.2188" thk.
fixed spring    -
Spit Mk IV  159640  -   -   110 lbf/in
at the wheel    5 leaves
3x.38"+2x.25"
swing spring    -
Spit 1500   159640  -   -   110 lbf/in
at the wheel    5 leaves
3x.38"+2x.25"
swing spring    -
GT6 MKI     307324  2.38"   -   86 lbf/in
at the wheel    8 leaves
.25" thk.
fixed spring    -
GT6 MKII    308499  3.47"   -   93 lbf/in
at the wheel    6 leaves
.234" thk.
fixed spring    -
GT6 MKIII
(pre KF20001)   308499  3.47"   -   -   6 leaves
.234" thk.
fixed spring    -
GT6 MKIII
(post KF20001)  159654  3.47"   -   93 lbf/in
at the wheel    5 leaves
2x.3125"+3x.375"
swing spring    -