S&S Cycle Prostock Racing Camshafts Part 33-5085 - Manual (Page 2)

INTRODUCTION AND SPECIFICATIONS
The S&S ® Prostock cams are designed so that the position
of the cam lobes can be adjusted on the shaft, allowing
the engine builder to customize the timing of the cams.
Lobes are meant to be welded in place when set to the
desired position. Typical intake center line angle range
is 105° to 116°. Typical exhaust centerline angle range is
110° to 116°. Prostock camshafts are available for 1986-
'90 (four-speed) cam geometry only.
1. Camshaft Component Identification
A. Identify camshaft lobes. There are two identical
exhaust lobes, marked 5085B or SS492 and two
identical intake lobes, marked 5085D or SS490,
The valve Opening and Closing sides are marked O
and C. See Picture 1.
B. Identify cam shafts and gears. Note the timing
dots stamped into each gear. See Picture 2.
2. Initial Lobe Positioning And Press
NOTE: Clean all parts thoroughly with an evaporative
solvent before assembly.
A. Place the lobes finger tight on their respective
shafts with the opening and closing sides correctly
positioned. See Picture 3.
NOTE: The initial positioning does not have to be exact,
but should match the cam lobe positions in picture 3
within a few degrees either way.
2
Intake Exhaust
Valve Timing
Adjustable Adjustable
Open/Close
Valve Duration 279 ° 298 °
Valve Lift with 1.625:1 Rocker Ratio - .800"
Centerline Adjustable Adjustable
Lift @ TDC Adjustable Adjustable
S&S ® Prostock Camshaft Specifications
Picture 1
Picture 2
Picture 3
SS 492 exh. lobe SS 490 int. lobe
C
C
C
C
C
O
O
O
O
1 2
4 3
O O C
dot
dots
dots
dots
Rotation
Rotation
Rotation
1 Rear
Exhaust
2 Rear
Intake
3 Front
Intake
4 Front
Exhaust
Rotation