The motor is a replacement (metric motor), so I am unsure as to what exactly was ever done to the pump. I am thinking it is untouched.
I have to check the WOT passes again, but I seem to remember it changing slightly as it went to redline (slightly richer).
Yes, based on the plug readings and now the wide-band, it sounds as if it will take me awhile to figure this one out.
Agree with Peter. I installed a 292 and had a aux linkage installed on my '72. it's not perfect and I've been planning on installing a WB sensor for final tweaks.
I'm not familar with a '74 tii but once you change the cam on tii w/ changing the cone (cam) within the KF, you do risk you A/F ratio being off at some point. You've changed one variable (breathing) and the "dont' touch" screw is not progressive for fuel.
The "best" solution would probably be to get your KF re-built to account for the cam. A second solution will be to install an aux linkage and a third solution might be to tune according to your driving style and make some compromises.
Good luck on finding you balance. Let us know where you end up.