High output alternator recommendations

I run the ProFlo4 EFI, in tank 340lph Areomotive fuel pump, electric fan, and the mad bypass on my cars and both have no issues at idle holding 14V even with the headlights and A/C on. This voltage is verified by the dash gauge hooked at the fuse block and the ProFlo4 data which is sensed at the starter relay. Stock alternators. My bet is you have a wiring or alt issue.