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63corvette · 08-12-2009, 07:58 AM

JJ, you want to stay away from the aluminum valve bodies in my opinion.
I build race transmissions and that has been my experience.
Ten or fifteen years ago I worked with B&M on their development on their alum. valve body for a powerglide.
Those just did not work out very well at that time. My personal feeling is that the pistons and valve parts are steel and with the body being alum the growth rates being different the clearances changed as the transmission heated up. That in turn affected the consistantcies and another problem was if the pump pressure ever fell below 150 to 170 at idle when you applied the brake the car would back up a short distance. That issue was a major one as you stage the car. I first thought it was a clearance issue with the band for first gear or the reverse pack but found it was with the body.
Just my opinion is that you stay away from the alum bodies.
Most of the GM bodies that have been converted to a brake are all done the same.
The major difference on all the manufacturers is whether they use a spring on the reverse apply piston in the body.
Most all the major manufacturers will work the same if the brake solenoid is shimmed.
The torque converter also has an affect on how fast the car leaves and if it matches the cam torque band.
JJ, with a Davis car you should be able to go red anywhere. I can with mine which is an 07 model.
Good Luck at the races.
My 2 Cents
Rick

08-12-2009, 07:58 AM	#5
63corvette Senior Member Join Date: Mar 2007 Location: Canyon, Tx Posts: 551 Likes: 127 Liked 353 Times in 102 Posts	Re: Another transbrake thread, & tires JJ, you want to stay away from the aluminum valve bodies in my opinion. I build race transmissions and that has been my experience. Ten or fifteen years ago I worked with B&M on their development on their alum. valve body for a powerglide. Those just did not work out very well at that time. My personal feeling is that the pistons and valve parts are steel and with the body being alum the growth rates being different the clearances changed as the transmission heated up. That in turn affected the consistantcies and another problem was if the pump pressure ever fell below 150 to 170 at idle when you applied the brake the car would back up a short distance. That issue was a major one as you stage the car. I first thought it was a clearance issue with the band for first gear or the reverse pack but found it was with the body. Just my opinion is that you stay away from the alum bodies. Most of the GM bodies that have been converted to a brake are all done the same. The major difference on all the manufacturers is whether they use a spring on the reverse apply piston in the body. Most all the major manufacturers will work the same if the brake solenoid is shimmed. The torque converter also has an affect on how fast the car leaves and if it matches the cam torque band. JJ, with a Davis car you should be able to go red anywhere. I can with mine which is an 07 model. Good Luck at the races. My 2 Cents Rick