im looking at buying a set of trick flow 10.4mm wires but one of the wires was burnt so it was replaced with an 8mm wire. will this affect anything? is it not good to run different size wires.
The size of the wire doesn't matter much. It's the resistance of the wire that you should pay attention to. For example:
Assume:
The MSD wires have 500 ohms of resistance per foot.
The "other" wire has 800 ohms of resistance per foot.
That means that the cylinder that is connected to the "other" wire will have a harder time igniting the combustion mixture that the other 7 cylinders. This can lead to improper running engines, worn out ignition parts and a sluggish feeling car. However, if the resistance between the two brands of wire are simialr than none of this matters and it would then be a purely cosmetic issue.