I'd be careful with that T5 though. Unless it is built up it probably shouldn't be in that car. They are only rated for 300ft/lbs of torque. I would bet that a stroked 351 has significantly more toque than that. I'd swap it ASAP. Then you could send the old parts to me so I can swap out the C4 in my 67 Mustang.
Swapping an auto to manual is a lot more difficult than it sounds. And more expensive too. I'm looking at at least $1500 in my Mustang and that is using a junk yard special T5...