spark boot connections

less than i year ago, i replaced some oem numbered plug wires with some auto store replacements. half of them are already in the trash it seems everytime i look under my hood, one of the plug wires has come off the plug, and landed on the equal length shorty cooking itself. leaving me on 7 cylinders.

its been less than a year and yesterday as i was warming up i heard a constant ticking, sure enough a FOURTH plug boot was sitting on the header arcing through.

QUESTION:what would make a plug wire, which snapped on firmly; wiggle,pop, or fly COMPLETELY off the plug???

the OEMs seem to be holding jus fine, but the new ones seem to not work. Who makes a plug wire that LOCKS on, since now im halfway back to where i started. i hadnt had any ignition probs but the wires were on there when i purchased the car so i have NO idea how old they are

those look like a decent price. as long as the clamp on good, thats what i need. the equal lengths havent been a problem, i mean, i think any header will burn through wires when you rest them on it