YEP.. what he said!

Remove the hose from the distributor vacuum canister, plug the leak, and with engine at normal operating temp and at idle, verify the initial timing setpoint. I like to set mine at 10 degrees btdc (before top dead center). And if your interested, slowly raise the rpm's and watch the timing tab and the damper timing mark, see how high it goes and when it stops rising, make a note of the rpm if you have a tach attached and note the highest reading btdc.