i replacwed the 3.1v6 with a chev 350 out of 4x4. when driving at night and sometimes at day my gauge shows between 8-10, normally its 13. the car batt is 720CA 600CCA and I recently added a amp and cant play it at night with lights on or major malfunction. Do I need a bigger alt than what normally goes on a late 70 early 80 engine or is the batt not big enough

 

your alternator needs to produce enough power to support your electrical system. The battery is already a decent size for our cars. I would put in an alternator that produces more power and a capacitor for your amp to draw less power from the electrical system. Just my 2 cents..