I'm not familiar with the Williams headers. But It just wasn't that tough with my Fentons. I used the linkage that Tom Langdon supplied with the Carter / Weber carb. That adapted the carb to an up/down action. Then I built a pushrod from the bellcrank on the side of the engine to the linkage. I used a piece of 1/4 steel rod from Tractor Supply. I used the original linkage as a pattern for the top and bottom, and bent the middle to clear the headers.
I suppose one could use coat hanger or welding rod to make a prototype for fit check, but it wasn't that complicated. The only tricky part was drilling the 1/16" holes for the cotter pins. The next time I'll thread the ends of the rod and use acorn nuts or nylock nuts.
Again, my experience was with Fenton headers, YMMV.
regards,
Leon
