Joel,
Tomm night and before you have a few,check your dizzy and just for good measure,undo the dizzy lift it a small bit about 15mm and when you feel the gear disengage roatate it slighty  making sure to note what way,try it both ways if need be and see how that goes.

When doing the above hold the dizzy housing with one hand and the shaft or button with the other so you can feel it disengage.

Is it one of those cheap brand dizzy's I've heard a lot about?

I have just noticed this thread as my computer was down for the last 3 days.
Your problem is simple.
Electronic dizzies must run on 12 volts. Your old points dizzy was running on 6 volts.
You have to bypass the ballast resistor wire in order to get full 12 volts to your dizzy. Also change your coil to an electronic one.
I guarantee that this will fix it.
Cheers, Chris.

I reckon Chris has hit the nail on the head.  It's a common mistake people make when going to electronic ignition from points.

Considering what I know about Fords would fit on the head of a pin and roll around, my question is, do Fords have a ceramic ballast resistor that mounts on the firewall (or somewhere else) or do they have a calibrated resistance wire like GM cars??

Also, after this is all said and done, I'd be interested to know if the car actually performs any better with the electronic conversion.  I only changed to electronic because I got sick of fitting new points/condenser 3 or 4 times a year.  By my hi-tech seat-o-the-pants dyno, my car ran just the same as it did with points ignition.

Andy it's not one of those cheap one's, it was recommended by a mate who has one.

Chris i've checked it all and replaced the coil with a new one. I think the new one is a GT30R or something. I looked everywhere and i'm not sure I ever had a ballast resistor to start with. Where would it be mounted if their were one??

At the moment I have a wire coming straight from the dizzy to the coil and the other one (which is positive) is connected to the ignition and splits off to the other side of the coil. No other wire's anywhere.

It sounds like a Bosch GT40R.  The 'R' means it's designed to use with a restistor, ie, reduced voltage.  The idea of putting 'resistance' in the wire going to the + side of the coil is to reduce the voltage.  By doing this, it prolongs the life of the points.  If you have a volt meter, test the voltage from that wire going to the coil +.  For an electronic ignition system to work, that wire must have 12 volts, no less.

***Disclaimer***  If the forum mechanic (or anyone else) wishes to correct me on what I've said, please do so, I'm just an old garage hack.        

Mustangs have a resistor wire built in to the loom. The quickest and easiest way is to disconnect the original positive wire to the coil and run a whole new wire from your ignition switch to the positive side of the coil. This requires removal of your ignition switch which is not that difficult in a '65.
You will need circuit tester to hook it to the right terminal of the swith because if you connect to the accessories the car will start but will not turn off.
Only recently we have done the same conversion thats how i know how to fix the problem.
Lots of GM cars and all Mopars just run a ceramic ballast resistor which is simple to bypass. Bloody Fords had make it complicated.
Good luck.  

ok i'll give that a crack tonight if I get a chance.

it's weird how the low voltage could get it idling but not at any revs....

Come on Joel we are waiting to see how many lines of the instructions you missed..
Good to see your getting dirty again though lad.:drink:

Hopefully its not the flux capacitor or rack and peanut steering.....glad I could help