Yep, had that happen to my mini starter with an MSD start retard, I put the big heavy GM starter back on, and eventually removed the start retard box.
Well the results are in..installed a Msd digital 6 box and now it starts great.ran this weekend with no problems. Even idles better.need to get a switch on my shifter for the retard in 3rd gear.would like to try and pull some timing out to see if it picks up.