Regular 289 - 
If this has the original damper,as you look at the damper from the front of the
car, the mark for top dead center is marked UDC (upper dead center). About a
quarter inch to the right of that is the timing mark which is 4 degrees BTDC
and the next on down is for the intake valve opening and is 11 degrees.  You
should not have to disconnect the vacuum as it is plumbed above the throttle
plates.  I would set the timing at the 11 degree mark instead of the 4 and try
it to see if you get any pinging.  If you do, then retard a couple degrees
until no pinging.

Ted
------------
Timing a V8 (Standard)

#1 cylinder is the Drivers side front cylinder
 
 loosen the bolt at the base of the distributor

 IF YOU HAVE AN ORIGINAL DISTRIBUTOR IN YOUR CAR, YOU CAN GET AN 
ELECTRONIC UNIT TO REPLACE THE POINTS AND CONDENSOR.  

 YOU ONLY HAVE TO SET THE STATIC (advance)  (UNLESS YOUR DISTRIBUTOR IS 
WORN, ETC.)  YOU CAN ATTACH A HOSE TO THE VACUUM AND SUCK ON IT TO TELL IF IT 
IS STILL FUNCTIONING.  

THE VACUUM SHOULD START ABOUT 7 TO 9 INCHES AND MAXIMUM OF 14 TO 18 DEGREES 
AT 13 TO 14 INCHES.  

THE CENTRIFICAL DOES NOT NEED SETTING, AGAIN AS LONG AS IT IS NOT WORN, 
SPRING MISSING, ETC.  THE CENTRIFICAL SHOULD START ABOUT 800 RPM AND REACH A 
TOTAL OF 18 TO 22 DEGREES AT 2000 RPM.  

THE STATIC SETTING SHOULD BE SET AT 4 DEGREES AT 650 RPM ACCORDING TO THE 
SHOP MANUAL; HOWEVER, IF  YOU HAVE GOOD FUEL, YOU CAN USUALLY GO A LITTLE 
MORE THAN THIS AND REALIZE A GAIN IN PERFORMANCE BUT WITH POOR FUEL, YOU 
MIGHT HAVE TO GO A LITTLE LESS.   

proper spark plug and gap =  .035" BUT IF GOING TO THE ELECTRONIC CAN UP TO 
.040" OR MORE.   TED