1976 mustang starter help?
This could be caused by a low battery or dirty terminals. First try charging or jumping the battery. Don't throw parts at a problem, diagnose first. There are a number of possible issues. Invest in a Cymer or Haynes manual & learn how to use it.
The starter needs a lot of amperage to crank, dash lights & fuel pump do not, so a weak battery or dragging starter can cause a no-spark/no-start.
Here is the test procedure for determining battery or alternator problem after requiring a jump start. Note, requires a voltmeter [$3.50 at Harbor Freight]
1] Check battery voltage on non-start vehicle. Will probably be under 12V. Verify good clean connections, look for cracked corroded or loose terminals.
2] Jump start. Note, always have the jumper vehicle running when performing a jump start, sounds basic but I actually had a friend who argued it should not, meaning he would be jumping with less voltage & could strand both vehicles.
3] With jumper cables removed & engine running, check voltage at battery. It should be 12.8V to 13.7V. If below 12.8V the alternator or voltage regulator are suspect. If in the range, the battery is either dead, low on water. If over 14.7V the voltage regulator is not functioning properly.
4] Failing those problems, with the vehicle shut off & the doors closed, disconnect the battery ground cable, put a 12V test light between the battery negative & a known good ground. If it lights, something, like an interior or glovebox lamp, is staying on. Remove fuses 1 at a time to find the problem circuit.
If you're certain that the battery has enough voltage & amperage [just reading 12V doesn't mean it will crank an engine] but it still does not turn over, then pull & test the starter.
If you get the chance, take some automotive repair courses, they'll save you a lot of money.
Take your time, be methodical & good luck!
I was an ASE certified Technician & GNB Battery, customer service rep.