Spark Plug Questions

[psears]

Hello,

I just switched out my spark plugs in anticipation of balancing my
Weber careburators. I took out 6 NGK BP6E S plugs with around a 1000 miles on them (good shape) and replaced
them with 6 Beru Ultra-X plugs. Now the car runs worse then it did before! It definetly feels like it's either missing on a cylinder
now (I pushed on the spark plug wire boots as hard as I could) or
the plugs are gapped incorrectly (they're supposed to be pre-gapped at the factory), or they just suck, period.

Question 1: What do you all think of these kinds of plugs?

Question 2: What should the gap be on these plugs or on any other plugs being used? (I have a 3.0L SC w/GE-40 cams, 10:1 pistons, headwork & Webers)

Question 3: What is the best, most accurate type of gapping tool to use? I have the round coin type. (I've heard that you can't use the valve adjustment blade type-they don't measure correctly for some reason)

Thanks!

psears

[82sctarga]

and that is that I do feel sparkplugs are crudely gapped at factory but because of handling and packing they can be off quite a bit. I buy a lot of plugs in my business and I find that in a set the variance can be .004 which is probably tolerable for some. I once had a set of eight and six of them were completely closed up. I would NEVER install plugs without checking them. also check to see if you crossed up plug wires,check at dist. end also.

[NYSCAR]

Just a thought- How old are your wires? Did the same thing - switched plugs, the car ran worse. Replaced the plug wires and all was fine. Sometimes all the moving and pulling and pushing of old plug wires and boots can cause them to finally fail.

Brad