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©2005 Edelbrock Corporation
Brochure #63-0389Page 2 of 2
Catalog #7880
Rev. 4/05 - RS/mc
• TIMING MARK ALIGNMENT:
NOTE: Alignment of the timing marks as shown below does not
always indicate Top Dead Center (TDC) of the number 1 cylinder
on the compression stroke. Chevrolet engines will be at TDC of
the number 1 cylinder on the exhaust stroke and the crankshaft
will have to be rotated one full turn before the distributor can be
installed and timed. If you are installing a new camshaft, the
crankshaft will have to be rotated already to adjust the lifter
preload for all cylinders. TDC of the number 1 cylinder
(compression) can be determined by observing that both intake
and exhaust valves are closed. Or, with the spark plugs removed,
by feeling compression buildup with your thumb plugging the
spark plug hole as you rotate the crankshaft towards TDC. TDC
will be indicated by the timing marks on the harmonic balancer.
1. Keyway marked with 0 (zero) is for standard “straight-up”
timing.
2. Keyways marked with A2, A4, A6, or A8 are to advance cam
timing by the number of degrees indicated.
3. Keyways marked with R2,R4, R6, or R8 are to retard cam
timing by the number of degrees indicated.
NOTE: It is advisable to use a ruler or other straight-edge to help
determine that the timing marks are properly lined up on the centerline
between the crankshaft and camshaft. “Eyeballing” it can lead to
serious timing errors and possible timing set and/or engine damage.
FIGURE 1
Standard
FIGURE 2
4° Advance
FIGURE 1
4° Retard
Figures 1, 2, & 3 are typical of Chevrolet timing mark alignment.
Edelbrock Corporation • 2700 California St. • Torrance, CA 90503
Tech-Line: (800) 416-8628 • E-Mail: Edelbrock@Edelbrock.com
TIMING MARKS
Line Indicates Proper
Timing Mark Alignment
(See Arrows)