Stock Diameter Perf.
Valve Springs
Chry
Ford SB
1.445
1.040
120 @ 1.680
295 @ 1.175
347
1.125
0.500

Howards Cams Hydraulic Roller/Mechanical Flat Tappet Valve Springs
Style: Dual
Outer O.D.: 1. 437"
Closed Pressure: 145 @ 1.750"
Open Pressure: 315 @ 1.150"
Coil Bind: 1.025"

Inverted Conical Valve Springs
1.055/1.280

Howards Cams Hydraulic Roller/Mechanical Flat Tappet Valve Springs
Style: Dual
Outer O.D.: 1.437"
Closed Pressure: 145 @ 1.880"
Open Pressure: 325 @ 1.250"
Coil Bind: 1.150"

Inverted Conical Valve Springs
1.295/1.450 Dia
118@ 1.950
375@ 1.380

Perf Hyd. Roller/Mech.
Flat Tappet Valve Springs
1.265
0.875
122@ 1.800
375@ 1.250
460
0.640
1.100

Howards Cams Hydraulic Roller Valve Springs
Style: Dual with Damper
Outer O.D.: 1. 437"
Closed Pressure: 135 @ 1.750"
Open Pressure: 285 @ 1.250"
Coil Bind: 1.125"

Electro Polished Performance Valve Springs
0.760 ID
135 @ 1.750
285 @ 1.250
Electro Polished

Stock Dia. Performance Springs
Chev
Chry
Ford
351W/C/M/400

Howards Cams Hydraulic Flat Tappet Valve Springs
Style: Single with Damper
Outer O.D.: 1.525"
Closed Pressure: 125 @ 1.875"
Open Pressure: 350 @ 1.375"
Coil Bind: 1.200"

Howards Cams Hydraulic Roller/Mechanical Flat Tappet Valve Springs
Style: Dual
Outer O.D.: 1.470"
Closed Pressure: 110 @ 1.880"
Open Pressure: 350 @ 1.330"
Coil Bind: 1.270"

Howards Cams Mechanical Flat Tappet Valve Springs
Style: Dual with Damper
Outer O.D.: 1.435"
Closed Pressure: 135 @ 1.680"
Open Pressure: 390 @ 1.190"
Coil Bind: 1.055"