This may sound silly, but it worked for me. Your symptoms are more problematic, but check the oil temp sensor and make sure all of the copper is still there to make a connection and that it is making a connection. . . .
I have the Southbend street dual disk with 205/100s and a 68mm turbo. The clutch isn't that bad to drive with. If you're in traffic most of the time, it might get a little tiring, but you'll get used to it. I dyno'd 610/1000 and it never slipped. So far so good.
I'm pretty sure what you just stated is correct. I am contemplating going 4.30s in mine soon so if you could follow up with the end result, I would surely appreciate it.
Man, I don't think you'd like the 71mm and 225s. It's just too big IMO. I realize our gear ratios are a bit different with me being on 35's, but as you said previously, my 68mm with 205/100s doesn't light until 2300 rpms. I really really want to try out a compound set up and see how it does with...
I have 205/100s right now and will be buying new ford remans and running 205-215/50s. I think with proper tuning that 50% nozzles are fine. I haven't run it personally, but my guess is that it will be a good combo.