47Lumbertruck
First off is the intake aluminum? If it is take either a heat gun or blow torch if the msnifold is off the truck.
Heat around the area where the oil filler pipe is, be carefull not to overheat it as the aluminum will staer to run.
As you are heating it move it around a little and when it is warm enough it will come right out.
(Do not let the torch flame touch the aluminum)
You should be able to do the same with the cast iron manifold it will need a little more heat.
Don't heat the pipe but rather the manifold itself.
I have done this many times, if you try the other way you will ruin the old pipe and possibly the intake, if Aluminum.
