yup, a ballast resister is needed. you probably smoked the coil.

http://www.msdpower.com/download/8202.pdf

but you did just install a master kill switch. how is it wired? the timing seems very suspicious.

EDIT
I found this: http://www.blowbyracing.com/msdblastercoil.html

says the primary resistance is 0.440 ohms which is pretty darn low.

lets look closer at the kill switch.