Tm Recoil Ak Gearbox Compatability

[HuttArmouries]

So I recently picked up and then sold a tm recoil ak. The actual mechanism and gearbox was great but I just didnt like the cast body especially for the price I was paying. Id like to get an ak gearbox seperately and try to fit it to a nice stamped steel body. Does anyone know how close the version 9 gearbox is to a version 3 in dimensions? Im no stranger to metalwork and hand fitting so if its in the realm of possibility I may go for it.