makaveli

Does anyone make shift kits or valve body upgrades for the 722.621 5spd automatic transmission? I looked everywhere and did not see it. Only for the 722.3 and 722.4. This transmission has been out for a very long time I wonder why there isn't one. Also I understand it is electronic but the electronics cannot increase hydraulic line pressure beyond what the current max is without hardware modification. Boring out a passage or stiffer springs is needed. Thanks for any info.