Stop in for a cup of coffee

OK MOPAR buddy called tonight and was telling me the problem he has.
He has a 70 Dart he's spent the past four years doing a ground up build.
Engine is a 360. He's started it a few times during the build and ran fine.
He got the car finished Saturday, and was headed to his first cruise night. Stopped for gas, got in turned the key and got one click off the started and nothing else.
Tried again and again one click.
Had a guy give him a push popped the clutch and drove it home.
He's check the ground all ok.
Put in two different starters and relays same problem.
He tries to start it off the relay with a screwdriver, nothing.
Battery is new and ok.
Checked everything else all appear working properly.
Starter is a mini type that turns quicker and used on the newer trucks...as he explained
He's stumped, thought maybe someone might have an idea.