1972 Demon 340 engine mods
For ignitions checks:
- Measure the resistance of all your spark wires. The 1 to the distrbutor should be 3k ohms or less. The other 8 should be under 10k ohm each.
- Measure the resistance through the distributor pickup with it disconnected; it should be under 500 ohms.
- Measure the resistance through the ballast resistor. Put the meter at the owest resistance scale, and touch the meter leads together several times and note the resistance readings of the leads alone. Then measure the ballast while disconnected and subtract the average resistance of the leads. The ballast resistance value should be under 1 ohm.
- Place the end of the coil's spark wire about 6-8 mm from metal and check to see that a good blue spark jumps that large gap.
- With the ignition connected and the engine idling, check the voltage to the ballast resistor at the blue wire; it should be no more than 1 volt lower than the voltage across the battery terminals. Then check the voltage at the other end of the ballast; it should be between 6 and 9 volts.
- How did you set #1 TDC? You need to make sure that it really is at TDC with a piston stop and then check to see if the damper ring is correctly at 0 on the timing marks. If the damper ring has slipped, then all your timing readings will be retarded.
If this is all OK, then you have done most of the possible easy ignition checks. (There are a few more possible).
- Have you checked the float level in the carb? Is this the Holley that you mentioned that came on the car?
- Next I would pull out the power valve and check for a rupture in the diaphragm.
- While doing that, clean out the bowl and metering block. You can also check the needle valve; with a hose connected to the inlet, blow air into the hose and then gently push the float up; it should stop the air completely when the needled valve closes.
- The idle mixture screws ought to be set between 1 and 2 turns CW from fully closed.
The above are just the basic carb checks.