I would like to start some discussion on options for getting a VSS to work on a carb to tbi conversion. I have searched both this board and the DIY Prom board and have come up with what I believe are some good questions.

The motor I am using is a 383 and it is going to a 4spd manual. The computer I am using is a 7747 (and I am still in the planning phase so any suggestions on a good bin for a 350 manual trans to start with would be appreciated).

I realize that the factory option of the optical sensor behind the dash is one way to go.

I have looked at painless and Jags That Run for the inline units that generate a signal from the cable.

Then, I found this guy on summit
Rostra VSS

It is a very similar unit to those mentioned above, except that it generates 4 pulses per revolution, or 4000 per mile, twice what is needed from the computer. It is also half the cost!

So, what I would like to try to do is make it work with my 7747. I have come up with a few options I think might work:

1) Use a factory style "buffer" that will split the signal down to half the frequency

2) Build my own pulse divider using some components (Flip flop and something for contact bounce to make a frequency divider) Has anyone ever done this for a speedo signal?

3) Not sure if this will work... If the signal is twice what it should be, the computer will see 120 when i am going 60, 50 when i am going 25, etc? So, my thinking is that when I burn my chip, try just doubling the values in the constants and tables so that the computer reacts the same way. I figure with the manual I am really only needing to tell the computer that I am above the threshold for it to control idle (to eliminate surging, allow for dfco, etc.), not program TCC control.

Any experience these options, number 3 especially, would be great. I am just trying to figure out one of the last details of this project.

Thanks!