T56 --> SGI-5C --> 92 TPI
 

So this might just be the last glitch in my 383/T56 swap. I have the SGI-5C box hooked up to the ECM, tried all the various recommended Output 3 and 4 configurations = no speedo. The only Output the speedo moves at all on is Output 1, with switches all off. Speedo reads maybe triple actual speed (120 mph at 2000 rpm in 4th gear with 3.70 gears.)

According to the SGI-5 manual the only application for Output 1 is for a 64,000-250,000 ppm signal; a T56 is 25-40,000, correct? Something's not making sense here. Most of the searches turn up an answer that just doesn't quite apply to my combo.

Any suggestions?