why do you need them? Are you running a power adder? Know that the quality of 6AL boxes has suffered greatly over the last 5-10 years since they offshored production. Personally, I would either get a Crane Digital ignition or a Holley unit.
If you are dead set on the MSD brand, there are tons for sale on the Corral, yellow bullet. Craig list,.... for a reason. New I'd go with Summit.
I'm going with a 408w and afr 205 heads from fordstrokers. I mostly like the launch control of the 2 step.. If I can't break into 9.99 sec quarters I'll add nitrous... Mostly I'm bored and wanted to get my line lock and
2 step ironed out..
Post pics of motor and rest of car! It's like car "pronz"!! Unless that thing is super light with a great suspension 9.99 n/a is going to be damn near impossible. Low 10's are definitely possible though. But like you said nitrous will get you there! Good luck.