I have no experience with running radials. But like all things, it all depends on your setup. I know I have not met one person who hasn’t gained ET when they made the switch. But it 100% all depends on your setup. Like if your car hits tire hard and can keep it planted, a radial will likely compliment your car. A radial tire will not be as forgiving or “recover” like a slick will. Meaning, if the tire hits hard, traction isn’t quite there, radial will be more likely to go up into immediate tire spin and the run will be ruined. A slick will be able to recover better from that little bit of lack of traction if the car is set up well. If that makes sense. Again, IT ALL DEPENDS ON YOUR SETUP. With a caltrac split mono leaf rear suspension and good rear shocks, I believe a radial would be a good way to go. I know there’s many benefits to radials. Just how willing are you to spend the money and try it. I will say, if you put them on and weren’t satisfied, there will be plenty of people who will buy them used.
Personally I would call Hoosier, M/T, or Phoenix and talk to them about what you’re experiencing and see what their thought would be to making the switch. Sending them video of the car from the side would also be beneficial.
I hope you make the switch and find success in it!