Since I don't subscribe to automatics, I'm not that familiar with T-350s, although I do know that there are 2 different length tail housings. If you have the tailhousing on your T-350 that is the same length as the P-glide, then your 350/350 should be a drop-in swap for the 283/glide. But if it is a T-400, you for sure WILL have to change to a T-400 yoke on the driveshaft and you may need to shorten the driveshaft for a T-400.
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Tom Parsons