mph to low maybe wrong gears?
i'm of the same opinion as you...whats up with pulling out the power valves,my carb i just got was the same way.the guy said it did not run right on his 427 chevelle.had stock jetting and powervalve plugs.i put in 4.5 power valves and put it on and it runs great esp at full throttle.
I don't know...
I do know I wouldn't run any of the jetting packages that the OP has posted. IMO, the last one is still ~10 steps in total lean. I made my suggestion based on it being a 4781 model. I bet it was in excess of 50HP short on power with the current jetting. Surging, no power in high gear, lucky it didn't barf on itself. Maybe that would have been a good thing that it just shut off.
4781? I'll stick with run 80-82 with a PV or 88-90 without. That should be in the ballpark, not sitting in the parking lot. It may want more jet, just have to run it to find out. Wouldn't be surprised if it picked up 5 tenths with the right jetting.
It went 6.92, roughly same ET as the Car Craft 480hp stroker engine in a 3350# car. MPH more or less than 96?
I guess on the positive side, it will maybe pull to 1100 feet now. :)
