My 1982 RAM with the 3.7L 1bl carb is losing vacuum and I don't know where. It's making noises at the back of the engine when I shut it off, but I am unable to locate it. Do these trucks have ported or manifold vacuum?

 

With the engine idling use a spray can of carb cleaner and spray it at any place there might be a leak. If the engine accelerates you have found the leak.

 

Not positive on the carbed engines but TBI use manifold vacuum. If the carb spray trick doesn't work, hook up a smoke machine to a vacuum line.

 

Not positive on the carb either but TBI has both.