Mapping my 340 ign curve

[Mattax]

There is an older mechanic here in my town with a Distributor machine, but he told me by phone that he can only spin point type distributors, he thinks, has never spun an electronic distributor

Yes. He can either rig something or contact Parmount (sp?) if its Sun. Hoppy might be able to help him too, but in either case its going to cross the border.

If its a Chrysler built distributor:
Some examples of guys adjusting the curve on Chrysler built distributors.
Here Rick works through and posts the effects of his changes
And an example of how that changes a bit with different combustion characteristics for later engine
I spill the beans on shaping the curve here


If its got Mallory advance, they're easier and harder:
Here's a thread with a link to another thread explaining the adjustments on them.
There's only so much that can be done with them due to the geometry.

Is this normal?

Hi, posted some picks of my dizzy,if you can zoom in there is white plastic shavings in the center where the spring clip is.I and getting ready to pull it out to add fbo plate. How would shavings get in there with the rotor on,and the rotor is white?

www.forabodiesonly.com

And long thread about slew rate but quickly in the beginining demonstrates why one does not want to stop the advance at 2500 or 3000 rpm.

Testing the HiRev 7500

Are these ignition systems as junk as many claim, or is the real issue in the misunderstanding of how the electronics work? You be the judge.

www.forabodiesonly.com

 

[Bewy]

In my opinion, the idle vac is low for that cam.
There could be many causes for low vac, including wiped cam lobe because the year 2000 was withing the danger period [ failures occurring ].

But assuming for now that the cam is good, I would concentrate on the easy things that can be checked.
Forget about the timing curve in the dist for now! Before you get to 5500 rpm, you have to get to 2500 first.
Fix the idle quality & cruise, first.
I would check this, in this order:
[1] Is the PCV hooked up? If so test it in gear & out of gear, idling. Put your fingers on the PCV cap. If you can feel vibration or pulsing, the PCV is not working. Easiest cheapest fix: cut off a 1/2" length of 3/8" bolt, drill a 1/8" hole through it, & shove in the PCV hose. If PCV has been disconnected, it is probably for the reason listed. Reconnect & use the bolt.
[2] Remove carb, for two reasons: to check the float level, should be 7/16". And......to see how much transfer slot [ in the pri bores ] is exposed at idle. If more than 0.060", that is most likely causing the smelly idle & surging. Ideal is 020 -040, with 020 being best. To avoid having to remove the carb to check, set the blades at 020 & 040 using the idle speed screw. At each position, using calipers, measure [ & record ] from the screw head to the screw boss, & note the slot position in the screw head.
[3] The engine likes more initial because they never had enough in the first place, even with stock cam!! GM engines had as much as 26* at idle with a cam that that 10* less duration than yours. Increase initial timing to 20*. Start engine & re-adjust idle mixture, & speed. Check vacuum & check T-slot position using the recorded measurements.
[4] Report back