Looking for a little advice on the timing numbers I just pulled from my 73’ Duster (backfire issue)
With a Holley.
First. Check fuel the level in both bowls.
Can't see which Holley you have but most have sight plugs on the bowl. Traditional sight plugs are located so the fuel level should be just at the bottom of the plug (primary) and a little lower on the secondary bowl. New big clear window plugs aer usually set near the middle.
Then check the primary transfer slot exposure under the throttle plates at idle are in the range of .020 - .040"
You can check with feeler gage or drill bits.
While you're at it, write down how many 1/4 turns in of the idle speed screw from just touching gets .020, 030, and .040. Then you'll always know how far open the throttles are.
The drill bit is next to the transfer slot.
The hole is the idle port.
With a Holley.
First. Check fuel the level in both bowls.
Can't see which Holley you have but most have sight plugs on the bowl. Traditional sight plugs are located so the fuel level should be just at the bottom of the plug (primary) and a little lower on the secondary bowl. New big clear window plugs aer usually set near the middle.
Then check the primary transfer slot exposure under the throttle plates at idle are in the range of .020 - .040"
You can check with feeler gage or drill bits.
While you're at it, write down how many 1/4 turns in of the idle speed screw from just touching gets .020, 030, and .040. Then you'll always know how far open the throttles are.
The drill bit is next to the transfer slot.
The hole is the idle port.