Little different perspective: I had a C5 behind a 302 with approximately 375 horses at the flywheel for several years. This was my daily driver. I rebuilt it on the back porch with a lot of plastic laid down for cleanliness
I can't recall the specs on the flexplate. I know it was 28oz balance though.
I am putting in an AOD right now. I think I will like it a lot better. I know my 3.89 gears will like it