B'sBowtie

I have a 75 Nova SS with a 72 MarkIV 402(punched .03 over) and am haveing problems with the front brakes locking up when it gets hot. I had to replace the 11in brake booster with a 9in because of valve cover clearance(went with 7:1 rockers, so I needed taller valve covers). I also have headers and it seems that the brake lines run within a couple inches of them. Is there some way of telling what the real problem could be. I'm up for any suggestions as to how I can fix this problem. Would going with a non-power brake master(getting rid of the booster)and higher temp brake fluid help with the problem....PLEASE HELP!!!...I really want to drive it this year. I will answer any questions you might have to help me fix this.

RacerX

did you replace the brake combination valve?