Break-In. How Long?

I fixed a Performance Issue with a Ballast Resistor!
The First Time I gave 'er the onions it revved well up to about 3 1/2 r's and started to stumble and miss...
Runs Well at W.O.T. to 3 1/2 r's and then runs like s**t,
I've thought about this all day... wondering what did I change that caused this?
I got a Halifax Distrib, Accel Wires, NGK Plugs and an Accel Yellow Coil. I tried to match the Coils resistance with an Equal Resistor @ around 1.6ohms (Too Much!)
I put My Old Resistor (.7 - .8) back in there tonight, changed Nothing else and Bam! She Runs Like a Striped-A**-@pe!
Now I just have to summon the nerve to run it passed 4xxx R's... 3rd gear at 4000 rpm was about 75mph and Loud! Lol Too Much Fun!