Some of the above comments note that noise is noticeable above a certain speed, whether it be 40, 50 or 55 mph. I would not disagree, but would point out that increased noise does not equate to any sort of limitation of the engine or drive train
In 2015 I drove to the Reunion in Kansas City, MO, from Mesa,AZ, which one way is 1200 miles. I cruised at 55-57 in my '51 Chevy half ton, which brief stints up to 65 when merging, for example. The truck is stock, except for Coker radials which are the stock size.
I have driven my '50 COE, with a later 235, on the freeways in Phoenix at speeds up to 57mph. That is with the rear differential in high range which I recall is about 6.10.
I have a trusted mechanic friend who still has his father's '52 Chevy sedan with the stock 216. He says he got it over 100 mph, on a long downhill mountain grade. That engine survived his teenage years and runs great today.
Sure, these trucks sound like a singer sewing machine at 40 mph, and at that speed are very enjoyable to drive. But that does not mean they are not capable of a bit more speed.
Kent
