I have a 85 c-10 305H automatic truck that refuses to send a spark from the distributor. I have tried everything I can think of and still no spark. Here is a link to the whole list of what I have done and the results...
http://www.fixya.com/ThreadAsker.aspx?thid=8186767

 

OK. Original no spark caused by broken lead from pick up. Continued no spark problem was 3 defective Cardone remanufactured distributors. I got tired of installing and returning so I bought a new Accel complete unit, dropped it in and it fired right up. Stay away from reman distributors!!