idle dies

Your springs are fine,and so is idle timing between 12 and 16(with v-can disconnected/plugged). It should idle fine in gear at 550 or even a tad less.And it should not jump up more than 100 to maybe 150 in Neutral.
That it does not, seems to indicate that either, the intake valves are leaking(possibly the lash is too tight) or the carb is lean. The valve lash is easy to prove with a leakdown test, but if your vacuum is about 12 inches or better at 700rpm, then I wouldn't bother yet.
So that takes us to lean idle circuit. And that takes us back to post #4; the TDC mark,the T-port sync., and the cracking screw.