Classic/Antique Car Repair: 1931 ford A, inline fuse, transistor module

Question
Hello i need some direction other than the one i have been down, laughing, i have a 1931 ford coupe "A"  i keep blowing the inline fuse off the starter, i have replaced the ground strap for the body to batt. i have a 6volt positive system as original. the only up grades that were done is a nu-rex transpark system that has been working great for two years and i went to a paper filter on my carburator. i took the day and replaced any and all bad wiring i could see if the ends were rough or if there was a heavy rub in the wire sleeves, i have replaced the coil, plugs and cap. and put new fuel lines on. i am only telling all this so you get the idea of the projects i did today but what propted all this clean up was i was driving and suddenly it cut out and died and never turned back on i could get it to turn over but it never started and i seen that the inline fuse was going bad so i changed the fuse and turned it over and it went bad again so i am frustrated and a bit lost. please help if possible. thanks

Answer
From what you say, the in line fuse is connected to the ignition. The question now is what else is fed off that fuse? If nothing else, then the problem is in the ignition system, perhaps a problem with the Nu-Rex transistor module. What size fuse are you using? Let me know the answers to these questions and we will go on from there.