I have a Power Master starter on my 63 thats been on it since 2006 and has never given a problem. On all my other cars including the 400 in my sons Dart I use the Mopar starters. The one on my sons Dart is listed for the V/6 (3.9) truck eng and has been on it since 1997 and never had a problem. But I also agree with Doug & Gus as you have to test the system out and see what the problem is. The voltage drop test is a very good test for the starter system in finding bad cables or connections.
I wish I could do a voltage drop test along the cable but no way I can get a probe on the starter terminal with hot headers. Aren't the terminals on your mini-starters up against the block basically? I can't even get the terminals on/off the starter without pulling the starter first and rotating it.
