Don't know how I missed this thread until now...
Awesome work, Sitckman!
... and you refered to my 89 Caprice as a "build", a mere engine swap compared with what you are doing.
I am interested in the kit you installed in your 200-4R. So far, nothing has been done to the transmission in the 403 wagon, even though it has 250,000+ km wear and tear. It isn't slipping or broken, but I figured the additional torque of the 403 over the 307 will push it to its limits. My thoughts are to use it until it needs a rebuild and then have it built strong. I like the idea of the manual shift kit you are using which allows full automatic operation in OD position. Does this also operate the lock up torque converter? This was an issue for me, since in '89 the torque converter is operated by the ECM, which no longer is being used with the 403. Right now I just have the clutch operated by a manifold vacuum switch, with a dashboard switch to override to unlock mode.