Qualifiers: I'm old and was never a good mechanic anyway.

Went out to take my '74 2L for a drive. Turned the key and started the engine. It ran for thirty seconds or so and then went silent. No juice. Is there a typical relay that might have gone bad? I replaced the ground strap a few years ago but I should probably check that again. If you have any suggestions, I would appreciate them.

Probably need to check ignition switch electrical portion, most likely it has split open.

No juice is a little vague. Does it turn over? Does the fuel pump prime? FI, or carbs? More info, please!

Stock engine and FI. Nothing happens; no prime, no instrumentation, no dash lights.

I would check the positive connections to the battery, could be loose or not making good connection

Thanks for the tips. I lucked out and it was a simple problem. I disconnect the positive battery cable when I park the car and my re-connect job was poorly executed. Thanks George.

Occam's Razor