Used the piston stop and my TDC is correct...
With the CAP, timing setting is 5d ATC. Since I was trying to go through the process of elimination and take the VCV out of the equation I disconnected it from the dizzy vac adv and plugged it off, set timing at 12.5 (as Without CAP) and the engine still pinged.
Retarded timing to 10, 7.5, then 5 and engine still pinged.
I checked for TRUE TDC using a Piston Stop Tool as 70bigblockdodge suggested and TDC is set correctly.
Next I will completely bypass the VCV and hook ported carb vacuum directly to the dizzy vac adv and check if pinging still present.
If pinging still present I will need to check if my vac adv is possibly leaking. I tried the "suck on the hose" method, but I'm getting constant air so I'm thinking maybe my vac adv diaphragm is leaking... may not be an accurate test? I'll get a pressure pump to test for more accuracy.
So it looks like I'm down to my pinging either being a bad VA diaphragm or the dizzy's curve advance is incorrect due to the dizzy's redesign for CA smog emissions as stated in 65cornonetRT's TSB.
If the VA diaphragm is good - rather than find a shop to recurve it, it might be best to just swap over to a complete electronic setup (dizzy, harness, control unit). I do have a Pertronix Igniter II that I was going to install, but if the actual curve is incorrect then the Pertronix won't really do me any good.
Anyone have any experience with either of the two units?
Proforms 66993 unit -
http://www.summitracing.com/parts/pro-66993
Summits Mopar 850004 unit -
http://www.summitracing.com/parts/sum-850004
The
Proform 66993 unit says
it's "bluprinted and features a factory-set performance advance curve" Whereas
Summits 85004 says it's "equipped with a Performance Advance Curve"
Since my 383 is a stock 270hp engine, would Summits unit work ok?
Well, those are my next steps. Please feel free to chime in with your experience, suggestions and/or opinions - thanks
Its just a reference, if the groove is not acurate it will not be halfway between your marks. First thing is check your dist cap/wires. Put engine on TDC and make sure rotor is pointing at 1 or 6 doesn't really matter which just so it is aligned with either