Do I need a PCV system?

The answer YES, I would not have an engine without it. It helps keep crankcase pressures down so helps with oil leak problems. You are re-burning fuel that gets past the piston rings so you get better gas mileage and best of all you are not breathing the crankcase fumes which is the same as breathing exhaust fumes!.
There are two ways to add the system to your engine, both choices will have a PCV Valve. That valve can be in the valley cover or in one of the valve covers. The valve must be supplied with a good vacuum source so it will flutter properly. If you have updated to a newer Edelbrock (friends don’t let friends use Holleys) carburetor it is easy to hook up a 3/8 hose to large nipple on the front or add a fitting to the rear for a cleaner look. If you have the early carburetor without a large port you can drill and tap a hole in the intake or simply use the power brake port in front of the carb pad. If you have PB already just put a Tee in and run both.. IT WILL NOT EFFECT THE BRAKES, Buick attached the brake booster and PCV to the same port starting in 1963 and kept doing that way until 1966(except 66 Q-Jet) … Here is where your choices are on the two systems, you can add a oil cap with a breather or an oil cap that has a larger hose that attaches to the air cleaner, this second choice is called a “CLOSED CRANKCASE SYSTEM” ..
HOW IT WORKS
At idle and cruise speeds where you have high manifold vacuum the PCV is sucking out crankcase fumes, the fresh air comes in from the breather with the open system and from the air cleaner in the closed system.. When you put your foot to the floor you have little or no vacuum at the PCV so fumes come out the breather. This is where a CLOSED SYSTEM is better, thou you have no manifold vacuum you have a large volume of air going into the carburetor and this draws the fumes out of the crankcase.