i just put on an open element on my 92 rs. i was wondering which line i needed to plug. is it the one on the drivers side? its small (about 5/16) and points towards the front of the car. or do i need to plug the other one on the passengers side? its about 2 inches in diameter and plugged into the back of the old air filter base?

 

If you've got a 92RS, then I think that's a Throttle Body engine.
Cap off the vac port on the front driver's side that you mentioned, but transfer the sending unit that's in the bottom of the original airbowl, that's your Manifold Air Temp Sensor and the car still needs that to provide the proper fuel mixture. Otherwise the ECM may throw a trouble code or two at you.
And let me know if that open element works for you, i've got the same engine in my '91 'bird.

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DR Stevens
Car #1:
1984 TA L69 H.O.
750 cfm Q-Jet reman. by Holley, 700R4 /w/ Superior shiftkit, 3.42 lim.slip, 4whl disc, underdrive pulleys, Accel HEI, experimental dual snorkel /w/ hood louver, some sort of weird 3" exhaust soon to be replaced
Car #2:
'91 Firebird/Formula LO3
all stock except K&N air filter (but not for long!!)

 

Oh DUH, my bad, you were talking about the crankcase ventilation coming out of the valve cover; DON'T plug that, buy what's called a breather cap and stick it in the hole on the valve cover. It sort of looks like a mushroom, usually done up in chrome.