If you just change your oil every 3000 miles or so you will have no problems with oil breaking down, If you have a early engine you should be using 10/30 or 10/40,or 30 or 40 weight and change it. The clearances are bigger in the earlier engine and you need the thicker oil to "fill" the clearances there,Its always been how you build them.And if you have a later engine put in the thinner oil because of the clearances are tighter 0/20 or what the manufacture tells you to use.People that tell you one oil is better than the next is telling you that because they get a good deal on their oil,All oil is good if you change it regular , Now i know there will be somebody to disagree but for the engines in these old bolters 10/30-10/40 is all you need.Just change it. It feels good to change the oil anyway in these old trucks,You have to work on them anyway.So why not change the oil and see what it looks like coming out.
http://s1055.photobucket.com/user/baldybenny/library/ 1936 1.5 wrecker,1937 gmc coe,1939 Chevrolet coe,1942 4x4 coe, 1942 coe,1946 dump,1947 2 ton dump,another 1947 2 ton dump,1950 coe,1967 c30,1937 cat 22,1936 Chevrolet 5 window foremans coupe, 1914 ford speedster.
