Give us a little more info.
The car did start and run?
You changed plugs, now it won't start?
While trying to start it does the engine turn over?
If the engine turns over, then firing order should be checked.
If engine does not turn over then battery connection is bad.

Before you changed the plugs, you said it was so rich it was like a flame thrower. Was there flames out the back?

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Stable:
1973 450sl
1978 red diamond ice vette
1975 steel blue convertable vette
2002 steel blue dakota quad.