First time out this year with the big block dart. Makes 820 hp with a stock front suspension and four link rear. Ran it for years with bias tires on all fours and no issues.
This year I put on the good year rear radials. They’re a tad smaller than the 14x32 good year bias. There 31.5. With 17 lbs of air pressure. When I get to the 1/8 mile the steering wheel starts going left to right and the car starts rocking back and forth and I have to let out of it or I’ll wreck. It’s not tire shake, I’ve had that a couple of times but that was a the starting line. Anyone have any thoughts on the issue? Thanks for your input.

First time out this year with the big block dart. Makes 820 hp with a stock front suspension and four link rear. Ran it for years with bias tires on all fours and no issues.
This year I put on the good year rear radials. There a tad smaller than the 14x32 good year bias. There 31.5. With 17 lbs of air pressure. When I get to the 1/8 mile the steering wheel starts going left to right and the car starts rocking back and forth and I have to let out of it or I’ll wreck. It’s not tire shake, I’ve had that a couple of times but that was a the starting line. Anyone have any thoughts on the issue? Thanks for your input.

Bias ply tires up front w/ radials out back is not your problem. I've been 156+ mph w/ a stock suspension 3800 lb car w/ 295-65 radials (15x8 wheels) on the rear and bias ply M/T Sportsmans up front. The car drove perfectly fine.