HEI Problems

[DHighway]

Hello my name is Dennis and i'am new to your wonderful site, I have a 67 CST C-20 that was my fathers truck then my brothers that recently passed away, he was a mechanic and rebuilt the original 327 block has 72k and updated to HEI distributor, have never had one problem with this baby until yesterday it just quit while driving it, like someone shut the key off! in checking with a 12v tester it has constant power at batt wire to dist, but has no power at tach wire while cranking, replaced control module, nothing, could it be either the coil pick/up? or the coil itself in the cap? please any help would be greatly appreciated, it is my only way to work, and had my brother not passé last month it would be running, thank you so much.