1969 Skylark Conv, just installed 455, can not turn off motor

My problem is my newly installed 455 will start, but not turn off by using the key. I have to smother the carb to stop the motor. During the install I placed the battery in the trunk, their was some wiring repairs made due to old wiring with failing insulation and I had to make a wiring distribution block. I am not sure how to locate the problem. I never had a problem with the column, ignition with the 350 motor. Not sure if The problem would come from the starter or the coil? Any ideas?

Thanks

 

Power wire to coil always on maybe

 

How would i fix that?

 

Get a test light and see what wire is always on after you kill the ignition with the key .
Something maybe got crossed

 

Bad ignition switch

 

It had a MSD ignition already installed for the 350 motor

 

Thanks i will try it tomorrow

 

I will look tomorrow.

 

Jason is totally on it. MSD instructions have a whole section of black on white printer toner devoted to this problem.

 

Thanks for all your help. It just needed a 1 amp diode on the brown #4 wire that is connected to the volt regulator.

 

I had the same thing happen when I installed a factory HEI in my 350. The diode was the answer.

 

X2 on the regulator, with MSD and the electro mechanical regulator the car will stay running with the key off.
With a new style ELECTRONIC regulator all is good.
I had this issue a few years back.