Charging system

[Weekender84]

I have a 84 k20 with a 350. All emissions have been deleted, just a carb, vac lines for brakes and blend doors. Electrical system is all original. I've been through about 4 alternators and 2 batteries in a year bc they over charge then eventually stop charging all together. I'm not sure what is going on bc there internally regulated. Rite now I have 11.6v at the battery and at the altenator and 13v when running (shouldn't it be 14?). It hit 18v going down the road a couple days ago and now it seems like if I have the headlights on and the blower motor running it drains itself and won't restart on its own until I jump it and let it idle for awhile with no acc. on. Also somebody told me that a faulty charging system may cause engine performance issues? Is this true? Thanks for any help.

[K20Detroit]

Are these cheap parts store alternators, or high quality ones? It could be a string of bad alternators, if they are the cheap remans/chinese knockoffs.

I'd get a new, high quality alternator, then;
Clean all of the underhood grounds, battery connections, etc. This will reduce stress on the new alt. You can add more grounds if you'd like.
The battery itself; correct size, good condition? The alt isn't working overtime to charge it?

Charging should be around 13.5-14v.
Performance wise, as long as the volts are high enough, the carbed trucks won't have performance issues. If the battery gets low, you'll lose some spark and the fuel pump won't be as powerful.

[Weekender84]

There the cheap ones, if I had to do it again I would have had the original ac delco rebuilt. I forgot to mention it has a msd ignition, but I just installed it that's why I asked about performance. Can I sill get an ac delco?

[Irish_Alley]

i know when i first got my cummins on the road i had a guy work on the alt. didnt have a problem before. he replaced some parts on it, after he did the work when i would drive it it would only charge at 13 v. then one day on my vacation while i was driving her from DE to VA i was watching the volts drop after barely making it to my uncles house at 1 am she was done. replaced it with one from napa and shes worked fine since then.