I'm pretty sure what I took out was this draft tube you speak of. However, I'm 95% sure that would have been an aftermarket item in '53. My other truck ('54 GMC with a high pressure 235ci) did not have anything in place of the expansion plug; just the original plug. It didn't even have one of the aftermarket oil filters one sometimes sees. So, although it might be ideal to have some type of PVC cannister filter or a draft tube, what is actually necessary? I'm hoping a vented oil cap will suffice, but I'm definitely open to clarification.
