rough estimate from what i've researched
4age - $800 (varies depending on what comes with it)
T50 - $300
AE71 crossmember - no more than $100 (shouldn't be at least)
tailshaft from AE71 - no more than $150
then you will have to think about diff upgrades, brake and suspension upgrades, fuel systems, tuning, wiring, labour.
etc etc etc
hope this helped, and good luck with the project :bash:
edit -
also, correct me if i'm wrong, but that looks to me like an ae71 wagon?
high roof, slanty front.
double check, if it is an ae71 wagon, the conversion will be a lot easier !