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.
Faster, Faster until the thrill of speed overcomes the fear of death...
71 Swinger - slowly collecting dust/parts 66 Belv. II - just a streetcar 88 Mustang - turbo LS beater
