I know this isn't a Buick transmission, but I am a Buick guy working on the car! My expertise is engines and manual transmissions, so this is new territory to me. I just put a 429 Ford engine with the original C6 behind it in my dad's 1970 LTD. Before putting it in, I put a B&M street/strip shift kit in the transmission. It shifts perfect--nice and firm on both shifts, so that part worked out great. The problem I have is that it won't downshift when I put it on the floor. The downshift linkage is adjusted right and engages fully, but it stays in high gear when I floor it. When I put the shift kit in I paid close attention to make sure the downshift lever still pushed on the pin in the transmission that it engages (the lever springs back on its own like it should). Anyone have an idea what could be wrong? I also need to adjust the shift point--at full throttle it shifts about 4000 rpm--about the time it starts to make power. How do I go about changing that to where it will shift around 5500rpm?
