As a generalization, because we don't actually know the engine or performance level it was built to, you could do the kinda-sorta universal default fix-curves.
Mutant is right on many points.
I'd use a Crane 99601-1 adjustable vacuum advance and the spring set that comes with it (the part number listed is for the stock GM points tyoe distributors, an HEI takes a different Crane part number).
The vacuum advance should be set to add 10 crankshaft degrees total. Set it up on full manifold vacuum after you set the initial timing to 12 or so initial degrees at the lowest idle the engine will go to.
As far as curve for the mechanical advance, start with the blue and silver spring each.
Pull the distributor and set the end play to .010/.015, then look at the underside of the point cam. You will see a pin protruding through the slot in the plate. If there isn't a bushing on the pin, you may need one to close the total amount of mechanical advance movement. NAPA has the bushings available, DP101, and the dealer should be able to get them if they don't already stock one.
Now comes the tricky part without a distributor machine. You need to mark the balancer with three more lines, so place the balancer in the tdc position, make a mark at the 10 degree line, move the balancer to put the mark you just made on tdc, make another mark on 10, etc. Three extra lines will be 20, 30, 40 degrees as the curve comes up, and the lines will read the individual lines on the plate, IE, line 3 plus 6 is 36 total at whatever rpm it gets there at. Read this again a few times, it will become clearer. Makes a stock balancer into a poor man's degreed one. Timing tape does same thing, only easier.
I would start the mechanical curve at 900 or so rpms, and limit it at 2,800 to 3,000 rpms for a stock engine. There should be 24 crankshaft degrees of mechanical curve.
What you should end up with is something like this for a start. Initial timing of 12 degrees, 24 degrees added to the initial as total initial and mechanical (no vacuum advance connected) for 36 degrees. There should be a 10 degree rise in idle initial timing with the addition of the vacuum advance from the Crane unit when itn is connected to full vacuum at idle, giving a total idle advance of 22 degrees.
If you have a distributor machine available and somebody who knoes how to use it, that way is the easiest to do the mods.
Please post the particulars of your engine/drivetrain and useage, and we can alter the above to maybe fit better.
As mutant surmized, you now have too much mechanical degrees of advance, getting there too fast, which makes the initial want to be lower than it really likes, and a vacuum advance that has too many degrees in it to help also.
[This message has been edited by IgnitionMan (edited 09-04-2000).]