I've got a TFI coil with a Duraspark distributor & just changed from a Duraspark box to an MSD box, worked about the same with either but the MSD is easier to hook up. Didn't think you could put a TFI distributor on it though, what would you use to control the dist.?
Check the MSD website, under 'user instructions', they've got a couple schematics showing hookups to TFI systems.
http://www.msdignition.com/ignition_4_6200.htm
And make sure you have a wire from the 'I' terminal on the solenoid jumpered to the 12 volt supply going to the control box or it won't get any juice while cranking.