Are your rear brake adjusters set up right?I fthe brake drums don't have a lip,the drums should just slide on comfortably when the start wheels are set right.
Now,if that's all right,I think you'll find that G/M purposely sets up the braking systems on their products so they Don't lock the rear wheels in a panic stop.
Anybody remember the X Car [Citation,etc.]rear wheel lockup problems from the early 80's?
For you guys who don't know or aren't old enough to know,what was going on was the rear wheels would lock up and the driver would loose control of the vehicle and get into an accident.
I believe that G/M got into some lawsuit trouble over this.
So IMO[and the opinions of the auto manufacturers],rear wheel lockup at speed is not a good thing to have happen.
Some of the earlier ABS systems I saw on trucks were rear wheel only.I suspect that the observations about rear wheel lockup at speed were the reason.
Now you're using a modified rear brake system to try and gain more holding power under boost at launch.A good thing in terms of drag race launchs,but be careful in regular driving,especially on rainy days.FUBAR warned me about this[he has the modified rear brakes].
We took Ron Josephs to task about this very thing on the other board when he asked us what we thought about his new brake booster kit.
He apparently agreed with us as he includes a momentary switch in his kit to engage the solenoid only when the button is depressed.
Otherwise the system is inoperative when driving down the strip[if I read the mag' article right],allowing for normal braking characteristics with the obvious benefits.Looks like he took our concerns to heart.Smart man.
