[gtoger]

SOLVED!



Thank you, everyone for the helpful suggestions.



The issue turned out to be a weak fuel pump. It made plenty of noise and if I released the line from the carb it would pump fuel into a pony tank. I have no way to gauge the PSI or flow rate but the old pump (when connected to the carb) would trickle gas through the filter, similar to what I would expect on a gravity-feed setup. With the fuel line disconnected from the carb the gas would "pulse" through the filter. The new pump will SWIRL and WHOOSH gas through the filter. You can tell when the floats in the carb bowl open the valve.



I just took it on a quick test ride and got her up past 60 MPH for some extended runs (my shop is right by the highway). No shudder, coughing or loss of power. I've got a ~25 mile trip to take this afternoon but I'm pretty confident it's going to go smoothly.



This particular installation does not have the "pencil filter", but does have an inline filter between the glass sediment bowl and the fuel pump. I changed the filter on the voyage home (50+ miles from the previous owner's barn to my house) and have put about 200 miles on the car in total so far and monitor no new sediment or dirt in the filter or glass bowl.


I used a small piece of wire cut from a wire brush to clean out the orifices on the carb then blew it out with cleaner. Since doing that and then re-tuning the mixture the car has plenty of low-end grunt and seems to be receptive to high-speed cruise.


Thanks again, everyone!