some where along it was changed to negitive groud
My guess is it was not changed, it was likely the battery was connected the wrong way by someone who did not know it was supposed to be positive ground. I can't tell you how many times I've seen that. Normally it doesn't cause any short term problems. One way to tell if it was truly converted is to look at which terminal on the coil is connected to the distributor. The + terminal on the coil should go to the distributor for positive ground as the points ground the coil when they're closed. If the negative terminal on the coil is connected to the dist, then it was likely intentionally changed.
The only problem you might have is the regulator or generator might burn up over time. To change it back, install the battery with the cables connected properly, then polarize the generator/regulator. You do this by a quick touch of a piece of scrap wire between the B (BAT) and A (ARM) tabs on the regulator before starting the car.
I don't know this for sure but I've heard if you convert the car to negative ground, and don't change out the headlights, when you turn them on it will get dark outside but I've never tried that (LOL)
