What is the typical output of an alternator at idle/cruise rpms?

[YGETV8]

I've ACTUALLY driven my T-Type a few miles in the past few days, but am a little concerned that my voltage outputs are too low. I see about 11.8-12.2 at idle and when just cruising I had the volt light flicker at me a couple of times! It seems to come right up to 13 or so with some RPMs, but I know my 147K mile GN kicks out 13.8-14.0 at idle, no problem! I realize that having an underdrive crank pulley (but a smaller alt. pulley!) and a trunk mounted battery probably aren't helping me, but... !? Thanks,

 

[TurboDave]

If measuring the voltage at the back of the alternator at idle, you should see about 14.2

 

[blackbuick87]

Your regulator might be going. I know its a pain but try swapping alternators maybe?