66' Barrelback, Battery Mounting

[KDG]

My 66' barrelback has what appears to be the original battery tray beneath the rear seat. It is mounted between the stringers but I do not have any other hardware to hold the battery in place. It also appears to be rather tight when we need to access the battery.

Are there any decent aftermarket battery mounting kits that can be used to mount the battery and box to the existing battery tray? Any assistance would be much appreciated.

Thanks,

Kurt