The T&D's originally came blue anodized. About three years ago they changed to natural aluminum.
Here are some quick T&D facts:
1. They are available in a lightweight true roller tip version just like the Jesel and Crowers out now.
2. If you run the production valve length the base mounts or the head bosses need to be machined down to get the geometry right. If you run a longer valve then you shim them to the proper height.
3. If you go with more than three turns on the adjuster the oil hole may not line up.
4. Some year models require a different pushrod length.
5. Valve cover baffles do need to be modified to clear
rocker arms. They "just fit" with the stock valves but will
hit if you mechanically overspin the motor or go into valve float.
6. We tipically see 10 to 12 hp from this mod, the results of a more stable valvetrain and slightly more lift.
7. These rockers are noisier than the production types.
Hope this helps,