Either valve cover, the driver's side is usually easiest since it has a twist off cap. The passanger side often has a breather tube to the air cleaner. Use a funnel, or you will get oil down the side of the engine, and it will burn on the exhaust manifold.
put on a new PCV valve.
Yes you can put a 400 from most any 60's year into the older pontiac. The only drawback is the length of the drive shaft. You might have to have your old one machined to fit the new powertrain.
301 pontiac engine mounts and 76 chevy nova frame mounts
Lol LL LL
No it is not. The correct weight oil for your car is SAE 5w30.
Someone put it there.