I've bought two separate "generic" plug wire kits, one from Amazon and one from Summit, and I've noticed that the plugs that go onto the cap have to really be forced down to "click" into place, and even then, some of them pop off... It's almost as if the cap post are too short. Are there different size\height post for distributor caps?

Luckily (?) I'm going to return the one I bought from summit since the coil wire boot is bad and is arcing.. I think I'm going to pick up some custom fit cables so I can cut to length, but I don't want to go down this road again with the boots not fitting.

https://www.summitracing.com/parts/tay-51006

 

I suggest Taylor wires.

 

Simple answer is Yes.

However, does your aftermarket Ignition Distributor-Cap use H.E.I Style Terminals...
or Early Chevrolet/ Non-H.E.I. Terminals.
The Same goes for the Ignition-Wire Set, that you purchased...
is it for H.E.I. or Non-H.E.I. ?

Either way cheap/ knock-off Parts are often manufactured with incorrect Dimensions or poorly-made wide/ loose Tolerance Dimensions.

 

Also Taylor Cable Products/ Vertex Magneto produces excellent Products from mild to wild.
I do not have any experience with their relatively inexpensive products...
they may not be so good. I have no idea.

I have used a substantial amount of their other products, which have all been fantastic!

I can not confirm this:
Pertronix Performance Products purchased Taylor Cable Products/ Vertex Magneto this past year...
supposedly quality control has suffered some since the acquisition.

Smaller Automotive Performance Parts Companies, have been getting snatched-up very rapidly by the Large Automotive Performance Parts Companies.
The Holley Performance Group has become the Second largest Aftermarket Automotive Performance Parts Company in the World.
Federal-Mogul is the First... and Edelbrock/ Competition Camshafts has become the Third.