I wish I had more experience with converter companies. I had a Coan 11" that worked great, but they said if I exceeded 500 HP it wouldn't hold up... and they were right. Once that car was dipping well into the 11s, it was like the converter's fuse was lit.

Tried a J.W. Performance 10" that was too loose for what it was sold for (10+% slippage), so I pulled it and put in a Frank Lupo Dynamic 9.5" which was very "popular" at that time (late '90s). But I don't hear people talk about Dynamic much these days...

In my car, that Dynamic worked really well, even after changing the engine and picking up about 50 HP over the original application. Now I've picked up another 50+ HP and am hoping it is at least still in the ballpark to get a new baseline.

In a friend's car that Dynamic spec'd a different 9.5" for, not so good... waaaaay too loose, so he yanked it and put in something much tighter. Very disappointing, especially because he knew how well mine worked for me.

ATI is probably an hour's drive from me (no traffic), but I've never been sure they were the way to go, either. They told me years ago that I should run an 8", which I thought was a bit absurd for a low-11 second car (at that time).

Dayum... I don't know that I helped the OP one bit, but I just reminded myself about how much I don't want to change converters again.