I suspect JimW's old rusted out system was acting kind of like "open exhaust", and leaned things out too much so it was slower - and also shortened the overall length which took low end away.
Well, the exhaust wasn't always rusted out and the the only leak that developed was when the glass pack flange broke. The rest of the piping and the other glass pack was too rusted to salvage.
What I was driving at in the original post that the 2.25" duals were creating poor situation for daily driving. The exact reason why? I can't be sure, but I would safely say there is a major difference between tuning an exhaust system for performance vs. daily driving. This was only the second time that I've modified an exhaust system and the effects are similar - more restrictive helps bottom end torque and open helps WOT driving.
Obviously, too restrictive would just be silly, but 'the word' on the street (and in most forums) is that bigger is almost always considered better - I say not. People such as David Vizard have done extensive research determining the effects of exhaust sizing, and I would not consider contradicting him. All I'm driving at is : in my nonextensive research, my original 2.25" duals were too big for 225ish HP 250 inline to use as a daily driver.
Regarding what GM was thinking/doing when they built the exhaust systems for inlines, I can't tell if they were using what was convenient because they assumed no one would be performance minded if they were buying an inline, or if they put alot of research into attempting drag every last fl/lb of torque out the 'little' inline. Who knows? Certainly not me, but it would seem logical that there wasn't a ton of concern at GM for how to build the best inline exhaust. The inlines were more of utililitarian engine, I could see a group of engineers sitting around in the 60's saying 'if someone wants more go, then buy a 366 or 402'.
Just my opinion and I wanted pass along my experience to others who might be building an inline for a daily driver.
p.s. - has there been recent issues with this site? This the first time since I started the thread that I could log back onto this site???
