I can't speak from experience, but here are some links to other forums discussing Crane ignitions. I ran MSD boxes for years and they seemed not as reliable as I had expected. I replaced my AL7 series with a Pertronix Digital 500 for less cost. Three rev limiters, adjustable multispark, and about 9 features based on rotary dials
https://www.corral.net/threads/crane...sd-6al.633890/
https://www.corvetteforum.com/forums...ne-hi-6-a.html
https://www.vintage-mustang.com/thre...runnin.346809/