904 wont up shift

Hey, I have a 904 that has been rebuilt (by myself and a friend) with a TCI Trans Scat performance kit, also made mods to the gearing (used an article from a mag about swapping parts from an A999 actually ended up getting the parts from a 78 newer lock up style 904, so now I have 5 clutch main hub, and lower gearing in first and second) am also using a converter from the slant six and 904 that were originaly in the dart, am using this set up behind a 360 thats got a single plain Streetmaster intake, Holley 600 vac secoondaries, headman 2 5/8ths headers, crane c cam.

My problem is that everything works excellent, shifts HARD from first to second, but won't shift into drive until what I think is about 40 45 mile per hour (speedo still aint quit right even after all the math and a new speedo pinion, grrrrrrr.) Shifts very very firmly into drive just dosn't do it till I am haulining. Fluid level is fine, pulled the valve bodie and double checked everything twice, I am almost 99.9% certain I have the kick-down linkage adjust correctly. Any body else ever have a simialar problem and what was your cure?