Here's what I found a few months ago when the subject came up on another board. Wire size, I googled it and MSD has a nice article on HEI coils. GM factory coils standard will draw about 4 amps, some better factory coils will 5.5 plus. The amperage draw is a limitation of the coil and module. There are performance coils that will draw 8 amps. The wire industry recommends as a "rule of thumb" 9.3 amps with 12 awg and 15 amps with 10 awg. 12 awg leaves some margin, 10 awg should work for the best coil you can find.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/181240/post/1357867/hl//fromsearch/1/#1357867

Larry

I don't own a vehicle that isn't old enough to drink.