Do 'I have to remove the existing transmission cross member for my T5 conversion? And if so how do I mount the master cylinder and clutch linkage?

 

The T5 will interfere with the crossmember. Specifically, the little fin at the bottom. I just cut it off.




Initially, I simply notched the crossmember, but once I started aligning new engine and drivetrain, I removed the center portion of the original transmission crossmember, leaving the pedal and brake mount piece intact.
On the F3 - which I have - that part is pretty beefy, and will need no bracing; not sure about the 1/2 ton trucks.
My crossmember also had a bolted-in plate at the bottom, so I made sure leave the bolt holes on either side of the length I cut out so I can retain that plate for a bit more stability

Edit: I am glad I cut out a larger section of the crossmember and didn't just notch it, since I had to drop the transmission to rebuild it (second gear was stripped, which I noticed on first drive), With the original crossmember in - even with the notch - this would have been impossible once the cab is on since the T5 extends past the trans cover opening.



I would brace the frame or use a strap to hold it together to prevent it spreading apart when cutting the center part of the crossmember out. The new crossmember for the transmission will add back this support.

I was able to fit the new transmission crossmember in under the brake booster without modification, but depending on how everything aligns YMMV. (Don't have a picture of this, unfortunately)

 

On an F-1 the crossmember is a few inches further to the front than on an F-3, and the crossmember is very different. You have to cut it out in the center, no question. The frame needs to be restrained while doing that or the rails can spread. Then you need to add a new crossmember for a trans support. Here are some examples of what's needed.

 

This is how I mounted mine.