Rochester and Carter Q-jets used a sintered bronze filter element in the carb body. These filter out the smallest of contaminates. The problem that occurred with them is when servicing the filter. The inlet fitting would get cross threaded or over tightened. I have a Q-jet that this happened to, and the PO sealed it with epoxy. They can be rethreaded with a Helicoil thread repair kit. The other problem would be loosing the spring to keep the filter against the inlet fitting. I prefer using this type of filter. It eliminates the in line filter for a less cluttered look, and place for fuel to leak.
They can be rethreaded with a Helicoil thread repair kit. 
The other problem would be loosing the spring to keep the filter against the inlet fitting. I prefer using this type of filter. It eliminates the in line filter for a less cluttered look, and place for fuel to leak.
