46' 726 dark headlight lens

Do you have the original smoke lamp or has it been changed to the typical post war lamp arrangement?  If you have the original smoke lamp, do you have the correct cover with the extension on it, or is the flat cover intended for the 671?   If the later, it might explain your dim light problem. The retrofit to a conventional smoke unit has the lamp clipped to the boiler front, which should not have a dim lamp problem.

I have the original lamp bulb Cover? I don't know what that is

If I were to switch to a conventional smoke unit, I know I need a new boiler front, smoke lever But do I need to drill out the boiler mounting holes large as the conversion says

Here is parts for the 1946 726 lamp smoke unit assembly. From Olsen's CD

I have those components in place

I have not worked on a 1946 726, but I will make a couple suggestions.

1) The smoke box cover assembly has a port on the front for the lamp to shine through to the lens in the boiler -- make sur the port is aligned with the lens in the boiler.

2) Clean the lens from the inside of the engine. Hopefully a Q-tip with something like isopropyl alcohol would do the trick.

I'll try that.