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We had the opportunity to test some torsion keys on a 2020 GMC 3500 AT4 HD we measured the factory ride height, ride height with the torsion bolts backed out, and with the torion bolts all the way in, we did this with the factory and aftermarket keys. See chart below.
We found the factory keys can achieve a "leveled look" with the rear only being 1 1/4" higher than the front where the rear used to be almost 3" higher on the previous model year trucks. The aftermarket keys do allow for additional "lift" than the factory keys as they are re-indexed to achieve a higher front height. The factory control arms will be the next limiting factor in ride height, at the 43 1/2" front height the factory control arms do sit on the frame stops limiting the down travel of the suspension. DO NOT run your truck like this, it may lead to premature wear on the ball joints and possible catastrophic failure of the factory control arms. If you are looking at running more than 2" higher in the front, 42 1/4" or higher, we would recommend to run an aftermarket control arm that is designed for a leveled truck with improved geometry. These are available from Cognito, FTS and soon Kryptonite Products, you can find them on our website under the suspension section. If you have any questions about leveling your truck feel free to give us a call or send an email and we will be more than happy to steer you in the right direction. 
| Keys | Torsion Bolt | Front Height | Rear Height |
| Stock | factory | 40 1/4" | 41 3/4" |
| Stock | backed out | 39" | 41 3/4" |
| Stock | all the way in | 42 1/4" | 41 3/4" |
| Leveling Keys | backed out | 40 3/4" | 41 3/4" |
| Leveling Keys | all the way in | 43 1/2" | 41 3/4" |