Waveski , 52Carl mentions shimming and that is the only "adjustment" you have to obtain the correct distance from the top of the frame to the bottom of the cab.
Now for the bushings, strongly suggest you remove the shackles and replace the bushings.
While you are at it, check the front mounts and their condition because they can affect the cab "level" plus you need to loosen them while working on the rear mounts anyway. If you have the factory assembly manual look on Sect 1, sheet 3.09 for the front mount instructions .....distance from bottom of floor panel to frame is 1.83" +.060 , - 0 .
For the rear mounts (shackles) go to page 3.12 . The distance there is .760" +.060, - 0 .
Its not overly difficult to do, I did it on my 1954 3604. It makes a big difference on the "alignment" of the pedals to their respective openings in the floor panel as well as the steering column, etc.... note that "level" is a subjective term when thinking about the cab getting those distances within spec puts the cab where it's supposed to be in relation to the frame.
PM me if you wish to discuss and we can.
Once you've done the work, you'll be glad you did.
Last edited by Dusty53; 01/31/2024 2:36 PM.
