camshaft

Ok, so my comanche v8 swap got put on hold. Found a steal on a 2001 cherokee with the notorious 0331 head crack. He said he kept driving it and lost oil pressure, so im kinda assuming the bearings are shot. I picked up a used long block with low mileage, and was told it was out of a 99. After more research, found out it was a 97. So, my plans are to swap everything over to the new to me longblock. My questions are:
Since im swapping timing cover(crack in the new one),should i use the balancer that came on the 97 or my 01? Flexplate looks close to the same, but the backing shield looks different, which flexplate and shield do i use?since im going from a distributor to cam sensored engine, would it work to have everything set to tdc, and just drop the sensor and everything in the same orientation on the new block? Any help would b geeatly appreciated. Thanks