Does it make a difference when using 7mm or 8mm plug wires with electronic ignition? RockAuto has a premium Packard 7mm silicone wire set for less than $30. 

I'm running one of the most powernul ignitions systems available with 7mm wires for about 10 years with no problems with the 7mm wires at all. The spark plug witres are arranged in the usual Y-block fashion with all brackets and gromets.  It's an MSD 6A box with "Blaster" coil. The wires are by Magnacore, on the pricey side but are excellent quality.  I have had other issues due to the high energy of this system buy to date, the wires have been flawless. Hope this helps...............

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Thanks, FD, it does, but I would like to know what issues you've had with your "high energy" system.

My MSD box in triggered by a standard Ford Duraspark magnetic trigger firing an MSD Blaster coil. The voltage produced is destroying caps and rotors. That high level of voltage produces ozone within the distributor which caused corrosion/rusting of the metal parts. I even had to replace one of the flyweight springs. I thought by drilling two holes in the top of the cap would alleviate the ozone issue and maybe it did. There was no more rusting of parts but the cap bakeolite and brass still continued to erode at a rapid rate.  I believe if I changed over to the wide cap with male towers as Ford did with the Duraspark 2 system, all would be well. I toned it down by using a Ford Duraspark module with correct coil and using the on board harness resistor. I could have simply used a Pertronix system and would never of had these issues but I'm a tinkerer that loves to explore and solve problems. That being said, the MSD system did seem to help  the performance  and for sure, sweetened the exhaust smell. 

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FD, I hope I won't be in the same boat. I bought a CRT tach-drive distributor and a Fast PS50 coil. I've decided to pass on the 7mm wire set, only because it's a universal set for many applications. Not wanting wires that are too long, and not yet sure how long they should be to clear Sanderson headers, I'll opt for Taylor Street Thunder 50051 cut-to-fit wires. The wires come with both HEI and female distributor cap ends. The CRT distributor has a female cap; the HEI-style cap for the tach-drive distributor wasn't an option, but you can choose a black, blue, or red female cap. I chose black. 

1/8” Holes in the same plane as the rotor tip will help with ozone. I started doing it over 35 years ago on a very high energy ignition on my Bonneville engine. On any engine with a rotor I clean the cap once a year.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I know nothing about the CRT strib. I'm going to assume that the heart of the CRT strib is a switching device similar to a Pertronix so you probably won't have the issues I had even if you run the system without a resistor. I think the MSD box being a capacitor discharge system with 3 sparks is a killer.  Just my thoughts on it.  I have been running the MSD box as described above for at least 5+ years and the engine never missed a beat. One spring day two years ago when getting my truck ready for the summer fun, I decided to open the distributor cap to have a quick look/see. That is when I discovered all the mayhem going on in there. As Dry Lkes Racer stated above, the holes drilled on the cap top solved the ozone issues but the rotor tip and "plastic" areas around the molded in terminals continued to become eroded away. Many years ago on this forum I tried to describe all the testing I did with a distributor machine using various ignition components wired up to simulate a complete system. The biggest change to spark intensity was when the ballast resistor was removed. Also, some coils proved to jump a wider gap when compared to other coils under the same circumstances. I'm still at it, like, since my Y-block is in a truck, there is ample room for the Duraspark wide cap. However, like 55Blacktie who will custom build his spark plug wires,  I'll have to cut the terminals off the strib end of the wires and crimp on with the special crimp tool,  proper female terminals in hopes of running my MSD box again. 

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