MSD -vs- Jacobs

1. Assuming you have Mopar electronic ignition now, and it is in good shape, I wouldn't expect miracles with either system. It would take a lot of miles to save $125 in gas.

2. Add the cost of an appropriate coil. There are various high-ratio aftermarket coils that will work well with the Mopar orange or chrome box, so consider that.

3. High power ignitions require more power to operate. This comes from somewhere (alternator) but is usually not an issue unless you go overboard. (An MSD 7 series system on a street engine is overkill)

4. High power ignitions require higher quality wires, caps and rotors. This stuff ain't cheap. OEM ignition will do better with the high quality stuff, so start there.

5. Call Jacobs and see if they'll support the used system. They used to have a pretty good warranty, but that was years ago. I fear used electronics.

I'm not trying to bash MSD or Jacobs, but I think you could you could probably do better with your money.

BTW if you do decide to upgrade your ignition, consider Mallory's fine products as well. Yes, they are more expensive, but the quality is there.