hi bonll
in '65 the ventilation system consists of a rubber hose that runs from the oil filler tube to a 90* brass fitting on the drivers side of the Holley 2818 carb. That fitting has a very small oriface in it that's just enough to allow some pressure and ventilation thru.
At the rear of the block is a black solid tube that runs up to the air cleaner housing.
See pic below. The tube circled in red at the rear of the motor runs to the air cleaner housing. The small fitting on the carb circled in red is the one with the small oriface in it and the hose runs up to the oil fill tube.
This system allows ventilation into and out of the motor.
A lot of people don't realize that small fitting on the carb is the closest thing to a PCV valve on the motor and ignore it and it can can clogged up.
The first thing I'd do is remove that fitting and run a piece of wire thru it to make sure it's clear and not clogged or blocked up in any way.
Having said all that........ have you determined WHERE all the oil is coming from? if not, clean up your motor as well as possible, run the motor and see if you can pinpoint where the oil spraying or leaking from the motor is coming from. Perhaps it's not from ventilation areas but somewhere else?
An intake or valve gasket leak? up thru one or more of the intake hold down bolts or the oil pressure line at the back of the block?