advance springs?

I agree with daredevil. Just find some springs that are about the right length and see what kind of curve they give you. I did try the Mr. Gasket springs a while back though. I think they are part number 925B. I put 1 Mr. Gasket spring and 1 light spring from a '68 383 factory distributor in my 440's distributor. It gets all the timing in around 2,700.