What alternator are you running? The Toyota Denso alternator charges 14.6 volts as low as 600 RPM . For the last 12 years I have had this setup with a single 650 CCA battery and a 91 Toyota truck alternator with zero charging and starting issues twocents

Gus beer

64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60