That steering bellcrank does limit engine lowering. I used the Fatman clip, and it drives like a dream. If you do go the Turner Brake route on Stude front end, don't try to adapt rack and pinion. It's a geometry mess.
I am going to say DITTO with the folks who said the original front susp should be used. If you have a lot of steering wheel play, as many do, you should look first at the steering bellcrank and the center pivot inside the front crossmember. I dono why Stude did it that way, but a small amount of play in the bellcrank bearings translates into a big amount of play in the steering. If you can take care of play in the bellcrank and the center bearings inside the front crossmember, the rest of the steering and suspension is pretty damn good. The ones with the Saginaw steering boxes are far better than the ones using the cheaper ROSS steering boxes. If you get a chance to get a Saginaw steering box , Lark Hawk Coupe -- GRAB IT. WHY BE ORDINARY ?
There seems to be more than a little bit of discussion on this site about what cons***utes 'traditional' and what is 'off topic' to this site. In particular IFS systems are frowned upon but as you pointed out late model transmission upgrades are tolerated. I know not every car of "the golden era of hot rodding" had a beam axle (not even the g***ers) but IFS late model component upgrades are particularly frowned upon. It is what it is.
While I don't know too much about the T5s transmission...I DO...know that the T-700-R4 is a trans. that should stay in the wrecking yard floor. How do I know, I owned one. I put one into my 67 Chevy II. After driving it for a while, I decided that if I broke it, a T-200-4R was going to go in. Unfortunately, I didn't break it. The T-200-4R is a MUCH better trans., in all areas. Better gear ratio, equally as strong, the T-200 is smaller overall. The better gear ratio is the main selling point. The T-700 that I put into my Chevy II was a full manual trans. I found myself...NOT using first gear for most of my driving. Just too low a ratio. PLUS, because it's so low, there is a huge rpm drop between first and second gear. Bad all the way around. That's one reason the T-200-4R was designed in the first place. The T-200-4R has a similar rpm drop in all of the gear changes. Mike P.s. - And yea, I fully agree with the "PINTO.."/Mustang II front suspension. Just a different "looking"...Stude suspension..!