About 13.6-13.8. My alternator is going out though so it fluctuates a lot, I’ve had this issue prior to doing the engine swap just have been bouncing between getting a HD alternator or stock replacement.
Also can I have reasons why people say don’t use a mechanical secondary carb on a street car? Vacuum secondary carbs open the secondaries when there is low vacuum (IE under load), correct? And mechanical secondaries only open when you open them (like over half throttle like mine are set I believe, I can feel it in the pedal when I hit the second set of springs). So why would it make a difference economy wise between the two if part throttle on a mechanical secondary never opens them? Or was that a question on why would I run a mechanical secondary carb on a street engine in general?