Thanks for the interest and feedback guys. I did some more checking and this I what I have come up with. I did consider cutting the face of the bracket and welding to the fire wall but decided against it for 2 reasons. Firewall flex due to all the push force and also with this style of master cylinder from a 1st gen, the way the seals work you would have to eliminate the large outer seal which I am sure would air leak and waterleak. I cut 2 pieces of angle and tacked them into position. I removed that very small piece that I used.
I also trimmed some off the bracket to allow pedal clearance at full stroke.
I think I also have figured out a way to re-use the stock chev return spring on the pedal by welding the pin back on in a slightly different position. I have to still install it all back on the cab to re-test the strokes etc. then mock up the spring. I am also going to install a hardstop for the pedal because right now the only pedal stop is the master cylinder inself. I will get some more pictures also. Hopefully this will help others out as I struggled a little bit on figuring out this one myself.