[Mart]

The crab units are normally pretty bulletproof. The problems I have had are normally with the cap arcing through to the spring clips. Had this a couple of times now, with the black caps. I also suspect I had a faulty rotor, but can't be 100% sure.

The other thing that can get a bit sticky is the advance mechanism, the outer part of the shaft sometimes doesn't rotate properly on the inner part and can generally give a retarded spark at higher revs due to no advance.

Other than that, you would need to progressively change parts from the good distributor into the bad one until it comes right. Murphys law would probably kick in, though and you'd end up with 2 bad ones.

Without the parts in hand, it's very hard to offer more targeted advice.

Bubba comes highly recommended and has the machines and equipment in place to find out what the problem is.

Mart.