Spark Plug wires size?

Hello to all. I have a quick question. I have a 1994 2500 GMC Burb with the 454 cid package. right now I have 7mm spark plug wires. I was thinking of stepping up to 8 mm or larger. I also plan on installing a Mallory Coil. Would this be a good combination for this beast. I am looking to SQUEEZE every bit of mileage from the truck.
Blessings to all who have read.
Thank you in advance
Chuck aka ulremember.:banghead:

Are you going to be using a controller to step up the spark?
If you are just using a coil with out any additonal modifications to the motor it will not be any better than stock. Reason being that it will only use as much energy need to jump the gap on the plug,

But isn't it possible that the secondary voltage drops due to an "weak" coil. I am having a miss at idle and at about 1200 r's. I have changed the fuel filter, manually cleaned the injector/sprayers, added some Lucas Fuel treatment and cleaner. It idles and runs soooo much better now. So I am thinking that the secondary voltage may be a lil weak.
Thank you for you fast reply.

Blessings to you and yours
Chuck aka ulremember

The guy who dyno-tunes my 383 Sub also is under contract to GM and several NASCAR teams. For street use he flatly recommends STOCK Delco caps, rotors and WIRES, says you can't do better.

I have a problem with this as dealer parts prices are about double what good name brand equivalents (Borg Warner, Blue Streak, etc.) at a chain parts store. And the Pep Boys/Checker/Schucks/Kragen frequently have a lifetime guarantee.

He also swears by NGK plugs.