[mikepellegrini]

There are three wires going to the starter - 2 larger ones and one small one. The small one goes to the solenoid and then back to the ignition switch (or DME). The largest wire goes to the hot terminal on the battery. If I remember right, the other larger one goes to the alternator.

My 83, the main ground strap is connected directly to the firewall (inside the battery box). On the engine side of the firewall in the middle above the sensor bracket, there's a connector block with another grounding strap which goes to a bolt on the bellhousing.

It'd be difficult to hook these wires up incorrectly because they fit only "just so."

Is it possible that you had the main wires into the starter hooked up correctly, but at an angle, so that when the engine turned over, the torque cause the connector to contact the firewall - creating the short? I had that happen once on my 951 - sorta. If you really got on it (torquing the engine over), the thing would short and the engine would cut out.

If there was a big short at the starter, you oughta be able to see evidence of it.