during everyday driving my car shifts properly and normal. when i am at about 80% throttle or more it does not shift at all.
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Have you changed rear gearing.. assume you are tuned since it's a 383. Here is a stock 2.73 "Normal Shift" table , note how the 2>3 shift command speed goes up with TPS%. At 80% it's 80 MPH , your tune has to match the shift speed to your gearing so you don't hit limiter. Note for WOT shifting there are two different tables used for shifting, do you shift OK at 100% TPS ?

 

i didn't drive the car for about 2 years it worked fine before i put it away and when i brought it back out it didn't shift right probably anything over about 70-80% throttle and up doesn't shift. I rebuilt the motor upped the compression and head flow as well as mufflex exhaust with long tubes. the computer was a pcm4less tune from the previous 383 motor.