Na, didn't think of an impact wrench, the hex may be a bit past that now but I'll give it a go at the weekend.
We only have one quarter mile event in our city each year, my converter went bad so I took a couple a days off work, changed it out & did some other things to get the car ready. When I took it ('70 383 Barracuda)out for a quick test run it surged at about 5K, although it felt like a lack of fuel my LM2 didn't go lean every time it surged but hooking up a fuel pressure gauge above the hood sure showed the problem. If I had of thought of the pushrod before I replaced most of the fuel system I may have been racing tonight!