HI MATE the 4kc and 4a motors and gearboxes are completely different eg:nothing intterchanges . I have owned and dismantled plenty of the ke70 and ae7i corollas over the years and i know these cars inside and out ! .T50 gearboxes are out there you just have to ask around or try asking me (I have 5 of them 2 of them still attached to 4a motors). Also the t50 uses a hydrualic clutch and you will need the hydrualic ae71 pedal box assembly for it to work properly THESE ARE DAMNED NEAR IMPOSSIBLE TO FIND and i have 6 of them . i am in the process of putting together conversion kits for 4age to ke70 and will soon have plenty of parts for sale soon on this site. ifyou need any info please message me CHEERS DOMENIC