No hard numbers to report - really not a numbers guy anyway.
What I can say is my 1300F EGT limit is much harder to hit and takes longer to get to. They also drop much quicker and go lower than at idle than with the previous exhaust muffler (with the "stealth" 1-1/2" core).
Having the lift pump ON made the flat spot move up higher in the RPM range but it's still there. This proves that the pump is a fuel restriction (even when it's on) which seems a bit odd. However I really have to be hammering on it to feel it, and it's a good regulator valve till I get a new transmission. I could route a by-pass with a ball-valve and a few "T's" I suppose, and just use the lift pump for the odd time I run it dry.
After three years of weekends with virtually every part of this engine in my hands, I really can
FEEL it's relief with the 2-1/2" exhaust. The entire vehicle just seems happier - as does the driver
Great to hear. Brings a grin to your face solving a mystery like this.
That it does. It finally feels like I can take this on a road trip. Been daily driving it to shake things out and it finally seems solid. I still wish I could quiet it down but I think most of the noise is just all the sheet metal. I have applied sound mat in various locations but not behind the cabinets.
BTW, how is your turbo oil challenge coming along?
Fair to middlin'... I think I've been overfilling it a bit also, top notch on the dipstick produces prodigious leakage, while bottom notch level the engine stays fairly dry. The valve cover is leaking for sure.
I spent most of one day off pressure washing the driveway.

I'm thinking of naming the van Valdez.
I'm thinking of naming the van Valdez.

Mine leaks a bit as well and I'm no longer sure where from. It's not enough to pepper the backside though, so I'm done with it.
I'm thinking of naming the van Valdez.

Mine leaks a bit as well and I'm no longer sure where from. It's not enough to pepper the backside though, so I'm done with it.
Valve cover leaks are a pita. How did you torque the valve cover down?
Not quite to the nut seat and even across all three.
I've done it so many times I can do it in my sleep (and probably have).
If your asking if I used a torque wrench - no, don't have one that goes down that low.