It's actually a replacement for the Holleys of the era, for use with the Loadamatic 8BA distributor, entirely different plumbing inside to capture venturi vacuum signal. Pep Boys, Sears and Western Auto and some Ford dealers were suppliers.
Both new and original throttleshafts measure .275". Even though the old books say the wear limit is .007" I like to ream the new bushings at .278".
I've made special tools to remove the old left and right bushings and another tool to replace them. PS, be aware that a lot of the...
Hylomar was developed by the R.A.F. for fixing persistent fuel leaks in the Rolls Royce/ Merlin Spitfire aircraft engines during WWII. You might say it helped win the war!