I have used Optima 6v battery in my 1954 Chevrolet trucks' battery trays, using the original battery hold down. As I posted above, the 6v Optima has to be placed on the diagonal on the original tray.

I also am able to use the 6v Optima in the stock battery tray on my 54/55 6v (positive ground) New Design GMC COE's battery tray.

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.