An additional course of action (in addition to your excellent and practical suggestion, WarEagle1): always end a trip driving your truck for at least 15 minutes at 25+ miles an hour (if possible).
That practice/action will remove all foulness (mostly moisture).
(side benefit: you will not need to change your oil/filter more often than the prescribed miles/time)
I have never needed a PVC set up in any of my small 47-55st 216/235/261 trucks (however, I did need one in my 2-ton 1954 COE).
