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I have heard there is a way to put a 91 le trans 4t60(5 wire round plug) in an 87 le 440-t4(4 wire square plugs). Can some tell me how to re wire the 4t60 to the lg3?

Yes, it depends on the valve body. I think '87 mid-year changed (all 3800's are the same) to be a direct connect some wires, '86 pcm needed a relay to invert a signal from the one gear switch. So you just need the plug and the schematic to verify. If you can dig up the schematic for the '87 I have the ones for the '91.