I have made custom choke rods to fit various carbs to my 66 273 Barracuda. I use a similar sized welding rod, grind the set out of a hacksaw blade to cut the C clip notch, do bends in vise.
I reference the choke linkage hole, with choke in closed position, to carb base using caliper. If 3/8" thermal spacer added, then add 3/8" to rod. I found that BBD, Holley 2280, and 71" Rochester 2, all bolt on, but have different choke hole to base measurement. Making new rods for each, made them each work perfectly. The choke bi-spring is set so choke is just set closed at about 68F, above that, not fully set. Also when warmed up, choke should go full open.
After evaluating all carbs, Rocher 2CV, is my favorite.
I forgot to mention there is also a sight variation in the lateral measurement of choke hole, for carbs. The bi-spring adjustment has limitations, keeping operating angle in range, avoids binding, for full operating travel, the #1 reason to make correct length rods.
