I attempted to mockup the trans and bellhousing. As I suspected the tiny Falcon trans tunnel wouldn't allow the Chevy bellhousing and Super T10 to fit, even with the engine tilted down in the rear. I ended up having to cut the trans tunnel out to get things bolted up.
So now I'll have to build a new trans tunnel when I build the firewall setback. Have to wled in the motor mounts first, and build the crossmember for the trans.
I guess I was making too much forward progress, so had to take a step backwards!