I am in the research stage of using a 4L60E behind a diesel. (Kubota)
The 4L60E needs an engine RPM signal input to the computer. The original gas motor got this from the cam position sensor I believe. The S10 guys that are swapping to early style gas motors have found that the tach output from their HEI distributors work for this input. Unfortunately neither of those inputs are available.
On a past diesel build I used an alternator pickup for an aftermarket tach feed. I don't know if this signal would work for the GM computer, but I doubt it.
The other needed inputs for the transmission control can be overcome. The 2nd hardest is the TPS (throttle position sensor). A factory unit can be adapted with a custom linkage.

Does anyone have any ideas??

 

I am using an ABS sensor and Rangemar is using the crank position sensor in the same manor reading notches made in the front pulley to run our factory tach. So I would think you could just use the cam sensor to do the same, you would just have to duplicate the # of pulses.

 

I do remember reading in one of the threads about someone spending a lot of time making a toothed wheel for that.
Crankshaft mounted would require half the number of notches as the camshaft wheel.
I was thinking that GM uses a voltage measurement from this output though. As the rpm increases the voltage decreases. There is a frequency in this output too, which the tach uses. I was thinking this was like a RMS (ac type) voltage signal. There would be filtering internal of the computer to take out the pulses. You may be right. Time for more research...

EDIT The variable voltage would be for an HEI ignition tach output only. It would not have been an element of a cam position sensor output, which is where GM designed this signal to originate. I was putting to much thought into the way the gasser guys were getting this signal. I have also searched on other gasser forums for this info. They talk about 4 pulses per revolution, but that would be for a V8. Since I am replacing a V6, I would expect to see 3 pulses per revolution, right? Again I may be getting carried away with ignition pulses. GM could have any number of teeth on their camshaft "ring". The best would be to take the thing apart and see what is on the camshaft, then make a ring with half as many teeth for the crankshaft. Mount the original pickup and problem solved.

 

Yes, you are correct about 1/2 the notches.