[jw hash]

the champion # 3 plug was used in the 1927 lincoln but for the lincoln the brass cap was nickle plated. I thank that ford was already using the #3 plug when the model A was first produced an that may be why they used them at first. but here is the big difference between the plugs, the #3 plug uses the same porcelain as the 30-31 3X if you take one apart you will see a step inside like 30-31 But if you try to put a 30-31 core in a #3 base the lettering will be under the upper nut, if you need some pictures I would be more then happy to send you some. I do have a #3 plug that still is nickle plated, John Hash