I did the same thing years ago on a 1970 Duster SB drag car, 340 motor with 5:57 rear gears and the 3.09 1st gear made you stay busy the first 300 ft. of the track I was told by one of the back then factory backed drag racers we would break it eventually but we never did If you don't beat on it hard from a dead stop there is no reason for it to not work I never noticed the change of the RPM drop on that drag car, my wifes 1968 Baracuda 318 4 speed car had the same trans I think and it drove nicely as a family car I'm in the middle of building a 1966 Dodge Coronet Deluxe(two door sedan) ex slant six three speed into a 440 powered 4 speed aluminum 833 O.D. car, I won't beat on it hard from the stop either It is way worst on the gear sizes inside the case than the standard 833 4 speed are