302 Camshaft Journal Sizes

So, I’m in the process of rebuilding a 302 J code motor. I pulled the camshaft and have been trying to identify it. It’s a Ford camshaft (has the Ford oval stamped in it), but the two letter code looks to be GD (the D is actually backwards). I suppose it could be D9 or D6, it’s kind of difficult to read. But, that’s only part of the question.

I got my micrometer out and started measuring. I’m not done with that yet, but just out of curiousity, I measured the journals; like 5 times. They’re different sizes. 2.02xx to 2.08xx. I find that odd. Then, I check my maintenance book and sure enough, they’re supposed to be different sizes.

Now, for my main question. Why?

My book only calls out the varying sizes for 302 camshafts. The journals for camshafts for the other engines are identical in size.

Ok, back to measuring. Hopefully, someone can answer that. The curiousity has got me.



I was told years ago that the sizes were largest from front to back. That was so that you had more clearance as you installed the cam and would be less likely to damage the bearings. The journals on the 289 and 351-W taper as on the 302 also. You can run a 289/302 cam in a 351-W and vise/versa. Back in the mid 70’s I had a 69 Cougar with a 351-W and could not find a hi performance cam for the 351-W, without paying for a custom grind, so I used a Crane Fireball 289 cam. On the 289/302 the #1 piston is at top compression stroke while the 351-W is at top exhaust stroke. I installed the Crane cam and wired my 351-W up on the 302 firing order. Engine ran great.