so i have a 83 chevy pickup 4 wheel drive. it had the stock motor,the 350 and the 700r4 transmission seemed to shift fine through all the gear with no hesitation. since then i rebuilt the 350,bored over .60 and with a bigger cam. i got it all hooked back up adjusted the tv cable to spec, and now it wont shift right. when you go down the road,witth your foot in the carb it seems to be ok. but if you are just kind of idling out and around it will hit all gears right into overdrive and chuggs along in a matter of seconds. if you romp on it it will down shift pretty good still. i have no idea whats wrong,ive changed fluid and filter adjusted that cable in allways possible and still no go. can someone please fill me in???