[elmariachi]

A word of advice. Start out by putting both heavy silver springs in, which will essentially lock out the advance at idle. Get your base timing and your carb idle set exactly like you want it, then come back and install the lighter springs. Otherwise the lighter springs let the distributor feed advance into the ignition around 950-1000 rpms and you may find yourself chasing your tail as the engine surges. Of course if you actually break it in on a dyno then your dyno guys will likely be on top of this.