5.9 magnum engine swap

[Fixitmg]

I am working on a 5.9 magnum engine swap into my 77 dually with a 4 speed. And I have a few questions for the guys who have done the swap before. first question is I am guessing I need to use the original clutch flywheel. 2) pilot bearing, which one should I use, I am guessing again I need to use the original motor pilot bearing number? the motors are supposed to be the same but this crank is different from what I read, but is the pilot bearing holes the same? 3) when I pulled the donor motor out I found what looks like a crank sensor on the rear of the donor motor flywheel. what is this, I don't understand why there is a crank sensor when they use a distributor still. Hopefully it is for the trans input speed and has nothing to do with the motor.
please help

 

[65 sporty]

Are you leaving the magnum fuel injected? Yes that is a crank sensor at the back of the engine and it reads off the reluctor on the flywheel. The magnum distributor only has a cam sensor inside. You will need a flywheel for a magnum with a manual trans

 

[Fixitmg]

yes I am , leaving the magnum stock. I did find out it was a crank sensor, which is what I thought. I really want to keep the trans, so I can use the grannie gear when I need it. and living here in Alaska I use it all the time.
so plan A is to purchase a 2001 flywheel which takes a 12 inch clutch and drill it to accept the 11 inch clutch. Dead Dodge Garage on you tube has done it with a stock 318 flywheel and a lathe which I don't have either of them.
Plan B is to just convert it to a Automatic, which I have a good donor truck to pull all the parts, I just think it will be a long labor then keeping the 4 speed.

 

[65 sporty]

Why would you want an 11" clutch over the 12? The 12" will hold more than the 11. What trans is in the truck now? NP435?

 

[Fixitmg]

well I don't know for sure on the trans code is I haven't been under the truck in a few minutes. But the research I have done is the 12 inch and the 11 inch clutch do not match with the number of splines and the size of the shaft, I have not been able to find a 12 inch clutch that matches the spin and size of shaft.
if you know of 12 inch clutch that will fit the original factory 4 speed in my 78 truck that would be helpful.