[Tigers] Timing deviates - advice needed

[Gary Pointer]

Once again, thanks all, for your responses.
Per Mayf's suggestion, relaying here a few details:
Model: Mallory Dual Point YC-449-HP
Motor: 302 CID. Year unknown. Stock internals.
Other: Moves smoothly to about 15 degrees advance, and 10 degrees retard. No
stickiness.
New points, rotor, coil, wires about 2500 miles ago.
A couple folks asked for pics: http://www.flickr.com/photos/tigerv8
The suggestion was made of installing a substitute, to prove/disprove
distributor issue. No many cats in these parts though (St. Albert, Alberta,
Canada).