Powerglide servo upgrade
 

In the past, I have used the dual ring or the Sonnex upgrade, which supports the servo pin at the cover.

I think the Sonnex upgrade may be unnecessary for 575 - 600 horsepower range.

Let me hear from those of you who build Powerglides for the milder engines. What do you use for the servo?

Re: Powerglide servo upgrade
 

As most stock / SS guys like to keep the pressure down to save HP, you don't have to do much if you're running less 200 PSI. For high horsepower applications like top sportsman with pressures over 200 PSI the Sonnax High Teck servo package works well.
Sonnax has some good articles on pin bias and other servo issues on their website.

Re: Powerglide servo upgrade
 

A lot depends on how much line pressure not how much engine horsepower .
If you are using a trans brake valve body and the line pressure is around 200# or more, I would definitely use at the very least the 28133HD return spring .
If you see any signs of what appears to be band slippage or overheating from shift overlap ,particularly on the middle of the band ,you might consider going to the 28821-10K ratio servo.
I have seen major improvements on band wear with that servo.
Significant enough that it can be seen on a data recording graph

Re: Powerglide servo upgrade
 

Tom, that is the Sonnex part I have been using, so I will stay with a proven deal.

Re: Powerglide servo upgrade
 

I have thousands of runs on my glide. Just has the stock type servo In it. 600 hp. Now it could not hurt to put one of the supported type in there if you have to buy one anyway