http://wot-tech.com/shop/3400/adjust.../prod_135.html
Just got these yesterday and they are really nice. Billet aluminum caps that use an O-ring/snap ring setup. Its not exactly a simple installation but if you have a vise, snap ring pliers, and a grinder of some sort, it is possible.
I will have some modification directions up once I do another from start to finish, as well as installation directions once we test them for total pressure range (probably 30-65 or 70).