You all may have seen the nice shiny chrome spark plug lead holders that are available from most speed shops and ebay etc. Well I installed a set of these on the ol HQ when it was rebuilt. Anyway, I was never really happy with the way the crate engine was performing as it always seemed to run like a piece of crap. There was always a definate miss or hesitation at various revs, including idling and i could never pinpoint it. After checking and double checking everything from fuel supply to plugs and dizzy I eventually found the culprit. Yes these nice chrome shiny bits were actually shorting out my plug leads to the point that there was visible burn marks on the shiny aluminium and a couple of the leads were cracked.
So my advice to anyone contemplating these is dont waste your money unless you have a show car that is not driven at all. They look great, but what a joke. Since I have removed them, the ol girl is running like a treat. "Now what can I do to get more HP out of a 350 HO crate engine" .
You can see the culprits in the pic below.

Cheers Trev...