tires warm up and car gets loose

My husband is new to racing and could use a little help.  He just started racing on a dirt track this year.  He runs an 86 Monte Carlo in the hobby stock division at Wagner Speedway in Wagner South Dakota.  They have one race left on Monday night, but advice for next year would be nice.  He does great in the heat race when the track in still wet and muddy, but is having problems in the feature getting the car set up right as the track gets more packed and dry.  He runs a beadlock rim on the right rear with about 20lbs of air pressure and runs around 25 to 30lbs in the rest of the tires.  He said when the tires seem to warm up then the car gets loose and doesn't handle well.  Any advice?  Not sure on the rest of the set up, but can sure find out.  

If my car is good in the heats I always tighten it up for the feature.Hard to say on the air pressure without knowing what kind of tires.I run asphalt take offs at 17lbs r/s, 8 to 12 l/s.The first thing I would try is letting the l/f down to 20lbs.this will add cross wieght and tighten the car up in the middle and off.  

Thanks for the info.  We'll try that.  He had the tires staggered with 215's on the left and 235's on the right.  We ran both 235's on the back and added a 1/2 spacer to the right rear (atleast I think it was the right) and it seemed to handle much better and that seemed to tighten the rearend up.  I'll mention lowering the tire pressure in the left front though. I'll have to check to see if we can run another beadlock on the left front inorder to let the air pressure down to 20lbs.  I'm not entirely sure what kind of tires they are.  They are kinda mismatched some are goodyear dunlaps, some are cooper, and there are some that are other brands.  Mostly 215/70/R15s and 235/70/R15s.  That probably doesn't help much though.  

I would check to see how much stagger was in rear tires.When it is A feature time you do whatever it takes to get the car to handle, but if you had 1" or less that might signal that you need a softer r/r spring,rear end not algined correctly etc..  

To tighten the car for a dry slick track you need more weight on the right front and left rear tires. you can get that with a smaller tire/less preasure on the left front or bigger tire/higher pressure on the left rear as you've tried. or hook up the front sway bar if its discoed that will also tighten the car up. If you front swaybar is hooked up take the tub out of the right side and use the screw to pull down on the right sway bar mount. these all should be legle in the hobby stock classes were you cant change much.  

There is so much more info you need to make any kind of change. The best advise I can give you is Racewise School. This school teaches everything about dirt racing from Late Models to Street Stocks. It was the best money I ever spent. www.racewise.net