This continous stream of oil is not uncommon with these lifters, which were used in the sbc after 1956, when the valve built in the lifter has failed open. This valve is not the chack ball that prevents leak down but one under the pushrod seat that limits the oil flow out to the pushrod and valve componants in the head.
The surest cure is to change the offending lifter but if you are frugal and inquisitive and brave, remove and dismantle(an exercise in itselt on a used lifter)and clean the lifter and you can probably cure it.
If all the lifters squirted like this it would probably lower the oil pressure on the guage but one "squirter" just increases the chances of leakage from the overhead.
However if there is some mist being carried back through the PCV it can increase the oil being consumed.
Run the hale out of it for a while and if it hasn't sealed off change it for self satisfaction-lifters are cheap and readily accessable on these engines.
