If your car can't handle being on the converter...change converters or add a restictor plate.
I've had to race 18 second pickup trucks at the Mopar Nats two years straight...nothing you can do.
No problems with the convertor. And I agree about the luck of the draw. But giving 8-9 sec in the 1/4 is different than over 7 in the 1/8th. Thats just a lot of track to make up in such a short distance. Heck when I'm running a mid 4 sec dragster he only has to give up a little over 2 sec.
Just my opinion like everyone else. I feel the faster car gets that break. Been on both sides of it. I'm just lucky to have many track options in Ohio. I can choose to race where I agree with their rules.