help with a 83 mustang.. I searched

- unsure. haven't fooled with vacuum advance dizzy in a loonnng time
-should. pretty sure its the same valve train
-intake should/will be the same
- if it was a 90 roller motor, then it is h.o.

heck to verify that it is indeed an HO engine. Remove the #1 & #3 spark plugs. Put your finger in #1 spark plug hole. Crank the engine over until you feel compression on #1 cylinder. Slowly turn the engine until the TDC mark and the timing pointer line up. Mark TDC on the balancer with chalk or paint. Put your finger in #3 spark plug hole and crank the engine 90 degrees. You should feel pressure trying to blow past your finger. If you do not feel pressure, repeat the process again. If you feel pressure, it is a HO engine.

No pressure the second time, remove spark plug #5. Put your finger in #1 spark plug hole. Crank the engine over until you feel compression on #1 cylinder. Put your finger in #5 spark plug hole and crank the engine 90 degrees. If you feel pressure now, the engine is not a HO model, no matter what it says on the engine.

Using a small carpenter or machinist square to mark the harmonic balancer off into 90 degree sections may be helpful here.

A 15/16 deep socket & breaker bar or ratchet may be used to turn the engine.

The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8

the dizzy will work but the gear on it won't last. you need to change for a steel gear

cast iron. where you put the wires makes no difference in what dizzy will fit. the advance points to the front of the engine because that is the only place it will fit. you just have to put the #1 piston on tdc and point the rotor towards #5 cylinder. that is where you put the #1 plug wire and go from there in the order you need. you then adjust timing by twisting the dizzy until you get your preferred setting. somebody else can exlain more. you should look at autozone.com for some tech articles on timing a motor.