Personally, I have an army of Snap On, Mac, Craftsman + KD distributor wrenches. It's difficult to get at that bolt easily unless you have different length extensions, a swivel or swivel socket. If I could have only 1 60's 70's distributor wrench, it would be this one. It's like my very fiirst wrench. https://www.ebay.com/itm/K-D-104-Distributor-Box-End-Wrench-1-2-9-16-3-8-Drive-12-Point-Vintage/263860651771?hash=item3d6f5206fb:g:vXMAAOSw0HFbZzD2&_sop=15&_sacat=0&_nkw=kd+distributor+wrench+104&_from=R40&rt=nc&LH_TitleDesc=0 The beauty of this thing, is that it comes apart in the middle, so you can turn it any direction you want, or put a ratchet on it. Because each end is different, it does mostly everything except metric. I carry one in some of my cars. Early KD 104's were made in USA. Later are not as good but still ok. There were a lot of cheap imported variants, too. This will do BOPC, Mopar, Ford, whatever. You can maybe find a clone on ebay or Amazon for like 10.00 new.
Here's a really cheap one that will work fine. The tolerances on the actual 1/2 or 9/16 size won't be perfect, and the center joint may wobble a bit. But it should get the job done, and it's cheap! https://www.ebay.com/itm/SHOP-CRAFT...l1313.TR5.TRC1.A0.H0.Xdistributor+wrench.TRS0
I have a distributor wrench in my toolbox for a Cadillac HT 4100 engine. Used it once about 25 years ago. Still there....
Thanks gents. Very helpful. My car has 3:42 non Posi....I was impressed that it would do a brake stand and a 2nd gear chirp when it shifted under hard acceleration. I need to open quadrajet up this winter and see what primary circuit is .....as the secondary circuit was super lean.
The best wrench I have found is the old Snap-On S9838 works great on Buick 350/455 They come up on Ebay from time to time. A link for reference: https://www.worthpoint.com/worthopedia/vtg-snap-16-distributor-wrench-9838-132023801
