electrical issues

[dwalker3310]

my son has a 1989 dodge dakota base model with a 2.5L engine. we have pulled engine and did a complete rebuild as he ran it out of oil and locked it up. We have now installed new motor and after a few other issues with water leaks from water pump we now have it running and well i might add. Issue is now its a hit and miss on wether it will start and if it does it dies and then wont start or even turn over. The alternator is brand new and the battery is brand new both have been checked and are testing to be good under load i am at a loss as i cant figure out what to check next. the in dash volt meter shows its not charging but the aftermarket gauge cluster i installed shows it to be charging properly and after all the testing done on the battery and alternator i feel they are both fine. please help as i am pulling my hair out trying to fix this issue.

[dwalker3310]

Ok real quick. I have now narrowed it down to a bad alternator again. Any ideas on what to look at that would cause this truck to knock out alternators do quick? Please any advice would help.