Does the vent placement vary on different distributor caps?

Hopper

Hopper

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My center spark connection was toast. Went to buy a new cap and rotor to replace but they only had the cap. I put it together by using the vent on the old one as reference. When I screwed the newly wired cap on it didnt fit exact. Cranked up but was missing.

When I turn the new cap around with vent on the bottom it fits like a glove.

My question is does that vent placement vary on different caps.

20210109_121041.jpg
 
As many distributor caps as the 68 year old hands have handled, they've never seen variation in cap design for a given distributor.

It sounds like you may have gotten the cap rotated when you swapped the plug wires, either that or someone somehow modified the previous cap to fit in a way that it wasn't supposed to.

I would do this -

1. Get #1 to top dead center on the firing stroke. Note rotor rotation while doing this.
2. Note where the rotor points. Install cap.
3. Connect the spark plug wire from #1 to the terminal that the rotor was pointing to.
4. Look on the intake manifold for the firing order.
5. Plug the spark plug wire from the next cylinder into the distributor cap next to #1, going in the direction that the rotor was turning as noted above.
6. Once you do that, the engine should start and run with no missing.
 
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Wierd all caps I looked at to buy had the vent on the bottom. The old cap had it on the top and did not look to be modified. Installed the cap with vent on the bottom and hooked wires up one by one from the old cap. Working fine. Hmmm mystery.
 
Could you see any markings on the old cap to tell you who made it? Would be interesting to research their caps to see if a) they've since changed their design or b) can justify why they put the vent opposite of what most others do.

Distributor caps fitting on the distributor are certainly not moisture tight, but they are supposed prevent accumulations of moisture that would occur to the extent so as to cause spark jumping within the cap. A vent minimizes moisture internal to the assembled cap/distributor while hopefully keeping water droplets or larger out.
 
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OEM# 12353866
DH 433
E4T2-12106-A

Also A7-216 printed inside

Looks like the part # comes up as AC Delco cap.
The only problem is the ones I see on ebay have the vent at the bottom by the squared end and mine is by the rounded screw end(the top) I will add pictures
 
Mmmm - my experience with ACDelco is they like to put their name on it somewhere.

I can clearly see "1" on the new cap - which is where #1 is supposed to go.

The old cap is blurred, but do I see what looks to be a "1" to the side of the same post relevant to the vent? (post at about the 3:00 position as pictured).
 
No #1 on top it is completely smooth. That just grime. It certainly through me off when hooking it up. Maybee that cap was made from Down Under 🤣🤣
 
Look at the bottom of the cap. The bottom being the edge that sits on the distributor body. There should be a little square piece on the cap that goes into a little square space on the body. There is no other way. FWIW, the squares may not be exact squares but they must match whatever they are.
 
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