Celica 5spd in Fc-how fabricate rear crossmeber?

[R Verner]

Just about to fit celica box in my Fc - not sure where to mount a rear  crossmember to? Thinking of welding anglline to either side of chassis  and running a cross-member from each side to surport gearbox. This would be a similar stye to later model holdens. I didnt think the box section that origanly run though the gearbox tunnel [that i have now cut out with original tunnel]would be strong enough to surrport gearbox , and was never designed for that job . Any help or suggestions muchly appeciated Thanks