Installed a Holly Sniper 550-858 on my 1980 CJ5 with the 258. On initial start up my battery voltage is dropping to 10.6 volts which doesn’t allow the sniper to operate. My battery tray is 10 5/8” x 6 3/4”. Replacing the battery tray to accept a larger battery would require removing the heater box which I would rather not do. Does anyone have any suggestions? Thanks in advance.