Not charging after MSD 6AL installation.

"The same reading" depends on CURRENT. Even with a bypass if you put enough alternator on the thing, and if the battery is low enough, you will see drop. The alternator generates regulated 14V depending on temperature-------the VR is temperature sensitive---------and the battery gets lower and lower in voltage if it's been discharged.......like say you left the lights on for a long time.

So if you could instantly switch between, say, a 35, a 50, a 65, a 105A alternator with a really drained battery, the larger alternators would show more drop than the smaller ones, but with high current flowing, there will be SOME drop.

The charge wire, unless you have a "one wire" is not as important. What is important is that both the ground and hot side of the VR see EXACTLY battery voltage.