my car has a stock geared rearend, but car came with a powerglide tranny, now car has turbo 350 and turning out high rpms at 55/60 mph. just normal driving from a stop goes through gears quick. its like i have it in low gear when actually its in drive.. hell on my motor .. just a stock motor as well.. any sugestions .. converter bad maybe? (350 engine)

Is it a rebuilt tranny? is the vaccum modulator new? I turned the adjustment screw in 5 turns on mine and it shifts much better mine was a flat head screw from what I understand most are allen heads I removed mine from the tranny and adjusted it much easier

whats the rear end ratio? more info please