I bought a really nice unit from Tim Oelerich at Concept Design Engineer LLC. It bolts to the head at the rocker stantion site, and works really well. I found it on e-bay and paid $86.00 with shipping. It is made for the FE engine, but can be used on engines with stud type rocker arms too.
Concept Design Engineer LLC
6645 Trenton Rd.
West Bend, WI 53090
(262)388-2509
Email:
conceptdesigneng@aol.com