what do i need to connect to make things work right

i have a 89 camaro with 700r4, 89 cluster with cable driven speedo.
i'm using a 91 firebird harness with manual tranny, and it had the electric speedo.

my cluster has a brown wire that's supposed to go to ecm's (speed input)

and i know there's a difference in pulse, 2000 to 4000.

i'm lost as to what i need to do.

 

This is a tough one. So your using your original drivetrain, and putting in a 91 firebird harness and 91 ecm.

I'm thinking you can just use a signal converter box (Dakota Digital SGI5c) put in between your optical sensor on the 89 speedo to the 91 ECM. That'll take care of the computer getting the correct PPM.

I'm assuming that your changing your 89 from MAF to speed density?

 

right, the 89 camaro had a 2.8/700r4 and we took a 5.0 tpi out of a 91 firebird and got the entire wiring harness

 

ok, well the signal converter box will give the ecm the correct ppm.
They're not very expensive around $70 new.