Permanently locked to where you set the timing, blaster 2 will be fine but make sure you run it without a ballast resistor, you cannot recurve it yourself, all you do is adjust your dizzy for the overall timing advance (ie: set dizzy to 15 deg, you will have 35 degrees of advance, set dizzy to 10 and you will have 30). There is a curve sheet that comes with the module, I wish I would have scanned mine.
I myself and a mate of mine had one, never drove mine, mates was a daily driver on gas, no issues.