I have been meaning to do this for a while. I purchased a used MSD Distributor and rebuilt it and modified it to use as a cam position sensor for my MS3 ECU.
Some things I found along the way, The bearing in the top of the distributor is an open style. I checked my other distributor and same thing. So any moisture that collects under the cap will drain into that bearing and cause an issue. I have replaced that R8 bearing with a sealed bearing to help eliminate a problem. Below that is a seal to keep the gunk out of the motor.

You can see from the pics that I cleaned things up and then modified the housing to hold a Hall effect cam sensor. I then setup a test bench to see how well the sensor for the new Crank trigger wheel and the cam sensor would work. I took a video of the two running together on the bench tonight.

If anyone has not been down this road and has questions, feel free to ask. I suggest everyone take a look at the bearing in their MSD distributor and replace it with a sealed bearing.

Hope this helps.
Dick

Here are more pics of the project..

I am trying to upload a video to youtube to show how my test bench works. But, It wants me to link to Google+.. I am not sure I have a Google+, so I will have to do more research on the subject.
I have more pics of the process, so if anyone has questions, fire away.

Thanks
Dick

just dont use their magnetic pickup in doing this...ok see in the later pic you did not, we did a simular deal a while back using one to trigger our EFI, worked great till pickup took a crap, then tried several more with no luck...chinese crap parts

What are you using for a cap?

I will be turning down a piece of aluminum to cover it, and plugging the old screen holes to keep it sealed. Hopefully there will be no moisture problems!!

ezstriper,
I had the MSD crank trigger with the magnetic pickup and the ECU does not like the waveform it produces, hence the reason to go to Hall effect sensor and toothed trigger wheel.

I also modified the oiler hole to help flow to the gears. Had a previous issue with cam gear, didn't see it until I shined a flashlight down into the motor and saw erosion on the teeth of the cam gear. Sent it to Crane and they did not see it with the naked eye either, so I didn't feel so bad about missing it.

Finally figured out how to post a video on YouTube.. Here is the test bench in action.

https://www.youtube.com/watch?v=KDm6FszSZDU

that neat as hell, what was the deal on the missing 36 ?

The crank trigger reads 35 teeth and then the ECU knows when #6 and #1 are coming up on TDC. The cam position sensor tells the ECU when #1 is on the combustion stroke and fires all the coils at the correct time and sequence.
No more cap and rotor and plug wires to throw spark at the plugs..

Here are some better pics of the crank trigger. I bored a relieve in the back side of it so it can center on the ATI dampener. The wheel on the test bench as not had that relief machine into it, yet. I had the wheel laser cut to my specs. 1/4" thick so there is little deflection when bolted on and the sensor has little trouble seeing the teeth..

Omc had a variation of the old northstar dis system, instead of a wheel on the middle of the crank ,for the bbc ,had a hall effect off the back of the flywheel. I thought the coolest part of that was you got a distributor shaft with basically a plug at the top ,bolts down to the intake . Lots of room for a blower now. And the early d.i.s.units ,when they were working ,had lots of output.
But your setup does give you manual control of individual cyl minor timing corrections via trimming the tin trigger wheel