I think the weather had to contribute a decent amount, and will agree with the others that the converter is too tight.
I have a similar mild 493 in my Plymouth, the 9.5" converter flashes to ~4400. Even the old off the shelf 10" "3000 stall" flashed to ~4k. I normally run 3.55's and a 28" tire and weigh 3700 lb at the line.
It is pretty light for an all steel 1/2 ton truck. Lol. What is your combo and what does it run? If you don’t mind me asking.
