How to insall distributer on 1966 ford mustang

Okay, you have to set the number 1 cylinder at TDC of its
compression stroke, and then drop in the distributor so the rotor is pointing to the #1 spark plug wire tower. This should start the car, then you could set the timing to spec with a timing light.

There are two TDC's of a cylinder- the compression stroke and the exhaust stroke. To find the compression stroke, take out the #1 cylinder spark plug. Put your finger over the hole. Now either turn the engine over by hand (with a socket on the crankshaft pulley-turn clockwise), OR have a helper bump the starter over in as short bursts as possible. As soon as you feel pressure on your finger- stop turning- the piston in #1 is rising on its compression stroke. Now check the timing pointer or scale by the crank pulley. Turn the engine slowly on over until the notch or mark on the crank pulley is right on the zero degrees mark on the scale. This is TDC of compression stroke-the piston is at top of travel in the cylinder. Put the distributor in so the rotor will be pointing to the #1 spark plug wire.

It is highly recommended that you have someone who has installed distributors in older cars before instead of attempting this on your own.
Installing the distributor wrong, even though not very likely, can cause the engine to literally blow up. More likely you will damage the engine.
Any Chilton or Haynes manual for that year Mustang will have the specific information you need to install the distributor. The positions of parts must be exactly as indicated. "Close enough" is not good enough for this procedure as it will damage the engine.

Get number 1 cycl . Piston up on compression stroke dot this by turning moter with starter put finger over plug hole u should feel the compression push it finger set timing mark on balancer to 0 o tdc install dist. Point rotor at the number 1 mark on dis cap install wires counter clockwise starting with number 1 one marked on cap the fireing order should be marked on intake