67 Galaxie Solenoid Problem
 

I was under the hood checking a couple things when I ask my wife to start it. A shower of sparks flew out of the solenoid. I bought an Accel replacement. I removed the old one with the wires still attached. Then I mounted the new one and moved the wires one by one to be sure they all went back the same way. However, now the starter kicks in and you can here the motor catch and fire but as soon as you release the key, the motor stops. It turns off just like you had turned it off with the key. Any ideas? Thanks!

once your engine starts\runs, the solenoid is not in the circuit any longer.
I'd say you have a lose or broken run wire..
check the coil connection Turn the engine to run and see if you get 12 v
Not start, run

There seems to be an intermittent short in the new solenoid. I put the old one back on and the car runs fine.

that's great.
best