distributor springs

Mr Gasket spring kit 925b says to use both of the light springs for mostly race and light cars.
From what I understand the heavier the car the heavier the springs needed.
Also those spring are light and sure don't feel like they could resist much do they?

Anyway, you could do what I did and swap em out, then put it all back together and use a timing light to see where the advance comes in.
I expect it'll come in at about 2200, so you might want to remove the slotted spring only and replace it with one of the light ones.
I think that would get you up around 2400-2500 before the advance comes in.

Then from that point you need to see what the engine likes to get it right, and there is no better diagnosis than MPH on a repeatable surface. (like a track)