i have a 71 pontiac ventura 2 that wont turn over. i have changed spark plugs.
Not "turning over" means it does not crank when the ignition switch is put in the "start" position. This is different than the condition where the car cranks but does not start. Changing spark plugs may help a condition 2 problem but will do nothing for a condition 1 problem. Tell us more and define the condition better. If it is a condition 1, the likely causes are corroded or loose battery/starter connections, weak battery, bad starter, loose alternator belt or bad alternator. Condition 2 is more complex but is diagnosed by checking for air supply, fuel supply and ignition spark.
the car cranks but does not start. battery is brand new. it was running for a week. when we changed out the spark plugs we noticed that we had an oil leak, and fixed that. but now it cranks and makes a very loud pop sound like when u pop a balloon.
Sounds like a cylinder is firing at the wrong time. Double check your spark plug wires to make sure you reconnected them in the right order when you changed the plugs. Do this at both ends of the wires and be certain you know where cylinder #1 is connected on the distributor end.
Check the points and condenser