Newly Rebuilt 351W keeps losing timing

[boblyon1]

I had a billet roller cam installed from Crower as part of te engine rebuild three months ago. At that time my builder checked and then double-checked with Crower who insisted we use a steel distributor gear. When we pulled the distributor the steel gear we found it was severely worn and abraded in places down to knife-edges, allowing the timing to slip. (the cam was harder steel and not worn at all) A third call to Crower resulted in the recommendation for a bronze distributor gear which we installed. Its running like a top now.

Although I've heard on this site that bronze distributor gears need replacing every 1000-2000 miles, my builder says that is not the case that they should give good wear. Anyone have comments on this? Thanks.