Just experienced this problem yesterday on the first long trip on the new rebuild with a brand new fuel pump and a new Rochester carb from Carb Exchange. Ran fine at 50 to 55 going down the mountain until I opened her up a little near the bottom of the hill. Started cutting out. Got to my engine builder where he had a timing light and set the timing. Took it out on the freeway up to 65-70 and it started cutting out till I dropped it back down to around 55. Speedo does not work so I'm guessing speed. Took the frontage road towards home at around 50 and it ran fine. Loaded ten bags of salts at Home Depot and headed home about 30 miles away. Was fine at around 50 till I had a line of cars behind me and speeded up. Started cutting out so would periodically pull over to let them pass. Runs fine at 50. This new rebuilt carb must have a float filling problem. That's where I'm gonna look first I think.

I feel more like I do now than I did before...
1946 Chevy 1/2 ton
1941 GMC 2 ton? flatbed
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