Batteries Plus - in AZ
Odessey PC680 battery - takes 1/2 the space as stock fits very easy. Seat cover available on Ebay $59 made to fit stock seat.
I had the PC680 in my 74 R75/6 4years + never charge works great fits without messing with the subframe terminals match up.
Also check mottard-eletric new wires for battery+ and _ plus the beacon 1 LED brake light kit. All money welll spent.