Hey all, i have a 77 elcamino, that has been tbi for a number of years, it was running a 90 model ecm, no speed sensor or neutral safety. i recently swapped it out for a 16197427, which i understand "Must" have a speed sensor. i have a cable speedo (which is wrong by about 40 percent) connected to 3rd gen camaro guages. (optical pickup with the little yellow buffer box) my question is can i run the signal from the little yellow buffer box into a drac in order to "tune" pulses so the computer gets the proper info? failing that, i assume the signal coming out of the buffer box can be fed directly to the pcm? any help appreciated, thank you.