I have recently acquired a 1988 formula firebird and at some point in life it has had a 400 small block and a 350 turbo tranny. The guage cluster is electric and someone has tried to run the cable before, does anybody know if there are analog to electric speedometer adapters. If I could tie it in to my original harness that would be awesome but I dont know if that is even a thing.

 

Yup you can buy analog (cable) to VSS (electronic) adapters from Dakota Digital and a few other online sources. There is also a speedometer sensor that will fit that trans that will put out the correct signal too. Check with a local transmission shop and they should be able to point you in the right direction.