I have a TH 350, with a 2800 stall, unknnown make shift kit, behind a 454 with plus 450 h.p. which has developed a severe shift problem. At first it would not shift into 3 rd, then things got worse and it would not shift into second either. When it would shift to second the engine compression would not slow the car down when I let off the accel. First and reversse are both fine with no slippage and when it had second there was no slippage. This came on all of a sudden and w/o warning. I checked the oil and it is fine and the vac line to the mod is in tach. Do I start pulling it out? I was wondering if the shift kit had a part failure. Any help is appreciated.