Help with an 83

Hey anyone please help if you can!

I have an 83 stang with a 351 stroked to a 396. My problem is I disconnected my battery a while back and then just recently tried to hook it back up. The neg. was connected but when I tried to attach the positive, the starter started revving as soon as I made contact. The engine doesn't turn over, but the car's starter instantly starts without the key in the ignition. Before I tear the whole car apart, does anyone have any ideas?

Thanks,
Dalydude

PS The car also has a MSD6A system with an MSD blaster coil. Could this be affecting it in some way? What about the ignition switch in the column?

Sounds like your starter soleniod is jumped somehow. Or like you mentioned it could be your ignition switch but usually it turns the car off on you all the time.

Lightly tap the starter solenoid on the fenderwell. See if that helps. Then replace it.

If you disconnect the small wire ("S" post) from the solenoid, and it continues to stay active, then the solenoid is bad, which luckily is cheap and easy to replace.