awhile back i had to take my gsr motor out and i put in a Ls engine just for a daily so i can rebuild the gsr...well i kept the gsr tranny and we put everything together, now my speedometer doesnt work at all... and it wroked fine with the gsr motor...also when i bring the rpms up to about 5 and try to go higher the rpm needle just flutters all over the plce and i cant tell when i redline...not sure why its doing this....anybody have an idea?

Ps when i h ad the gsr motor i had convtered it to OBD-1, so i have the conversion h arness and a obd-1 ls ecu right now..the ls w ehad laying around was an older one...any info would be appreciated, thanks