K Factor 
Approx. Stall Speed

Marking 
142 
2024 RPM 
A 
140 
1996 RPM 
B 
135 
1925 RPM 
C 
130 
1853 RPM 
D 
115 
1639 RPM 
E 
110 
1568 RPM 
F 
100 
1425 RPM 
G 
97 
1383 RPM 
H 
89 
1269 RPM 
J 
85 
1211 RPM 
K 
If you look at the tag that is usually on the bottom of the torque converter, there is a code with 2 letters, 1 number, 1 letter. The first letter is the application, 2004R's use a C, the second letter is the "K" factor, the number is the clutch type, capacity & travel in degrees, and the fourth digit (optional) refers to the cover style, number of mounting lugs and method of welding the lugs.
Cover Style: optional code
4th digit: A = Open cover (no converter clutch) 3 lugs with one weld per lug. (gas)
B = Open cover (no converter clutch) 3 lugs with three welds per lug. (diesel)
C = Converter clutch type, 3 lugs with one weld per lug. (gas)
D = Converter clutch type, 3 lugs with 180 degree weld on each lug. (diesel)
E = Converter clutch type, 6 lugs with 180 degree weld on each lug. (diesel)
F = Converter clutch type, 3 lugs, 245 mm style lug.
For the 298 mm torque converters 4digit code tag...explaned as follows.
1st digit= application
2nd digit= "K" factor (K x 14.2574)
3rd digit= clutch type
4th digit= cover type
APPLICATION:
B = 250 and 350 transmission,
C = 200/2004R, 3254L & pre 85 700R4
D = 85 and later 700R4 with 30 spline input
"K" FACTOR: A= 142 = 2024 rpm
B = 140 = 1996 rpm
C = 135 = 1925 rpm
D = 130 = 1853 rpm
E = 115 = 1639 rpm
F = 110 = 1568 rpm
G = 100 = 1425 rpm
H = 97 = 1383 rpm
J = 89 = 1269 rpm
K = 85 = 1211 rpm
CLUTCH TYPE: 0 = no clutch
1 = 300 ft/lb 43 degrees travel
2 = 240 ft/lb 46 degrees travel
3 = 290 ft/lb 44 degrees travel *
4 = 160 ft/lb 37 degrees travel
5 = 220 ft/lb 35 degrees travel
6 = 195 ft/lb 42 degrees travel
7 = 195 ft/lb 30 degrees travel *
8 = 300 ft/lb 44 degrees travel
9 = 290 ft/lb 44 degrees travel #
A = 300 ft/lb 29 degrees travel
B = 300 ft/lb 44 degrees travel
C = 330 ft/lb 28 degrees travel
* poppet valve
# static open poppet valve which is normally open and closes during acceleration.
COVER STYLE:
A = Open cover (no converter clutch) 3 lugs with one weld per lug (gas)
B = Open cover (no converter clutch) 3 lugs with three welds per lug (diesel)
C = Converter clutch type, 3 lugs with one weld per lug (gas)
D = Converter clutch type, 3 lugs with 180 degree weld on each lug (diesel)
E = Converter clutch type, 6 lugs with 180 degree weld on each lug (diesel)
F = Converter clutch type, 3 lugs, 245 mm style lug.
