Mallory kit pn 29014
i checked my records and my last combo was actually purple and brown.
the purple spring is loose and your curve will be quick until about
half way through when the purple spring adds resistance.

my current curve (vac adv disconnected)

initial 12
1000 16
1600 26
1800 29
2400 29
2600 32
2800 35

...this is on a 9.4:1 340 and seems to run good now.Prior to trying the heavier spring combinations the car would be fine when pushed and the next time it was pushed it would detonate badly.Very irregular as Rick says.hope this helps.