Timing question

Discussion in 'Small Block Tech' started by Mopar, May 26, 2019.

  1. Mopar

    Mopar Well-Known Member

    I put a 73 350 which was points, into my 75 century which is HEI. Should I change the initial timing from 6 degrees to 12?
    I the books I have list the points timing at 6 and HEI at 12. I just don't know if it makes that much difference.
     
  2. Canadian GS 350

    Canadian GS 350 Well-Known Member

    It really depends how much centrifical advance is in the distributor. If your using the points distributor you should stay with 6. Look up Larry’s timing sticky - it’s very informative. Which ever way you go, probably don’t want to see more than 34 degrees of total timing at wot. That’s what matters at the end of the day.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Timing depends on the distributor used, not the year engine. Most older cars have had their distributor changed once or more. When that happens, the timing specs for the new car become completely IRRELEVANT, they no longer apply. Distributors have different amounts of mechanical and vacuum advance. It varied depending on the year and engine size. The initial timing will depend on the distributor. You need to use a timing light to figure out where to set the initial timing. Without doing that, you are flying BLIND.

    http://www.v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/
     
  4. 1973gs

    1973gs Well-Known Member

    If I'm reading this right and installed a points distributor in a car that had HEI. You will need to install a ballast resistor or resistor wire to the coil. You should also run a wire from the "R" terminal of the starter to the coil. If you don't, you'll go through some points.
     
  5. BUICKRAT

    BUICKRAT Got any treats?

    Use the hei distributor and set your timing at 12. Car is already set up for hei.
     
  6. Gary Bohannon

    Gary Bohannon Well-Known Member

    Make a 30 degree mark on the damper with a sharp point. 1.75" right of the 0,use a hack saw blade to grove it. Brace the side of a hacksaw blade exact n the location. 1.75-1.76 to be exact. The 0 and 30 mark can be checked with a strip of tape cut to length so it fits the center of both groves. Looking over the front grille on the drivers side, the new mark will be to the right of the factory timing mark, clockwise.
    Now use the softest springs from a distributor spring/weight modification kit. A timing light will bring the advance up to maximum at about 2500 and you can set the 30 degree mark at 4 degrees. Always hit a little more throttle to 3500 or so to make sure that is the maximum.
    Be sure the vacuum advance hose is off the carb tube and that tube has a cap or smashed tape over it to prevent a vacuum leak to the engine until you have the timing all set.
    Then plug in the vacuum hose and set the idle adjustment mixture and then the idle speed.
     
  7. Mopar

    Mopar Well-Known Member

    Thanks for the help guys.
     
  8. Gary Bohannon

    Gary Bohannon Well-Known Member

    I was thinking of a big block Buick damper. Better make sure the 350 had same diameter damper for the 30 degree mark. Otherwise take the diameter x 3.1416 and divide the answer by 360 and multiply that answer x 30 for the measurement mentioned above.
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Same diameter, 6 3/4". Easy to figure out where to make a mark. Pi X Diameter = circumference, 6.75 X 3.1416 = 21.206. That is 360*

    21.206/12 =1.76" (30*)

    21.206/360 = .0589" (1*)

    Want or prefer a 34* mark?

    34 X .0589 = 2.0026"
     

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