87 firebird trans am 305eng 700r4 trans?

put a 700r4 in from a 86 camaro berlinetta (supposedly), in my 87 firebird trans am. Only problem it shifts way to early. Like 1800 rpms shifting through all gears. I press the tv cable adjustment on and tried sliding the cable all the way into the slider and then let go of the on. Then i turned the throttle lever on the carburator to wot. Test drove. Still no difference. Was this possibly from a v6 or do i need to change the governor, i heard there was like 3 diff ones. Help. I really dont wanna burn this up. Help. Also when im goin speedometer says im goin 55 but actually im only goin 45. Help.