If you have an engine that turns the RPM's that require you to use a 3500 stall then you would have gears between 4:30's - 4:88's 3500 stall converters were designed for engines that have a power range of 3300-8000 RPM so the engine's RPM would be at the beginning of it's power range when you leave the line. If your engine's power range is lower than that, you are wasting horsepower with a 3500 stall and creating more unnecessary heat because the converter is slipping when the engine wants to go.
If his car runs good with that set up then it would run even better if the converter and gears were matched to his engines power range.