24 degrees worth of advance, you can't mechanically advance 5 degrees or whatever skipping a tooth then bring some of that back for the low end by retarding the VP internally.
I don't know if the max timing on a VP is 24 degrees or if it advances 24 degrees, ie the timing is 8 or 10 degrees or whatever at idle then adds 24 more for a total of 34 degrees.
Someone came up with a nice mod for the VE pumps that gave them a significant increase in timing range which really helped extend the power band of 1st Gen rigs. Basically a spacer piece that gives the advance piston a longer stroke.