Mapping my 340 ign curve

KevinCar said
mopar electronic dist with "oem black box" and dual ballast.

That was added at some point 'back in the day'

KevinCar said
13-14" of vacuum @ 700 rpm idle. old school build from 2000, compression is 170-174, motor has low miles since build. I didnt build, bought in 67 dart. 727 tqflite, 3.55 suregrip rear.

Decent compression and vacuum for that cam IMO

KevinCar said
The car seems a little slow off idle untill 3000+ rpm, surges slightly at cruise, vacuum advance is disconnected and ports plugged.

Lets look at the timing. A little surge at interstate cruise could be a little lean in the main jets/rod combination. Go one step richer in the combo.

KevinCar said
not sure how to find a graph to "map" it?

A piece of graph paper or computer spreadsheet. Lets do it.

KevinCar said
initial is 12 degrees @ 650, 700-750
24 @ 1250
28 @ 1500
28 @ 1750
28 @ 2000
30 @ 2800
32 @ 3000
34 @ 3300

Timing on the vertical axis and rpm on the horizontal. Comparing your measurement with a Chrysler built Mopar Performance Distributor.

I don't know what's going on with no advancing from 1500 to 2000 rpm but I don't think the advance is why car feels sluggish to 3000 rpm. Might be a little too quick in for vacuum advance.

Yes with that cam, the engine probably would like more initial. But to do so you need to adjust the curve.