The second one you posted is the 70-71 style and the style used on the 72 350-4bbl and big blocks……..although the one you have posted has small beveled cuts in the middle of the hex edges. They did not do that until something like 79 or so. The one Larry posted is the one I would have for sale, which is a 72 350-2bbl type. ……..and for those that are really crazy they are all date coded. I used to have a bunch of the 70-72 style and would sell you the date codes you needed. I also have a deep impact socket with a slot machined into it to take them out of intakes without breaking them and for re-assembly. That socket has been loaned out on occasion and has toured the country a few times. Ask James Weinman. Duane
Thank you for all your help with this. I just put in all new vacuum lines and decided to take out the thermo ported vacuum switch. I have the air cleaner to manifold. I put in a new water temperature sensor in place of the TVS in preparation for new gauges I am putting in. I ran manifold vacuum the other day and it was running super great, but I will try ported now and see what it’s like as a comparison before deciding.
Anyone seen or used one of these? Hook to manifold vacuum, set initial timing, then you have complete control with your smart phone. https://progressionignition.com/
