Well, as I recall, the timing cover that will work with it doesn't have a dipstick tube hole, the later cars had them in the side of the pan. Since you've put the 289 into a Fox body, I'm guessing you used the later double sump pan. If this is correct, you should be able to use the late model front dress as well at the late model timing cover and pump just fine.
Now, did you use the early balancer? You don't say if it's an auto or a stick, but the 289 has a 28 oz imbalance and the late model 302 has a 50 oz. imbalance.