Flywheel and Torque Converter don't line up?

[56SS]

Well, I thought I was making some pretty good progress and nearing the running/driving state UNTIL...the flywheel doesn't line up with the torque converter correctly. I can see where the bolts need to thread in when looking through the flexplate, as you can see in the picture I attached, but they just don't line up close enough for me to thread them in. And yes, I tried all the different combinations that I could to try to get them to fit. As far as I know, I have a 4l60e from a late 90s full size van and a 5.3 from a 2001 silverado. I am wondering if getting the torque converter from a silverado will solve this issue, or if anyone else has ran into this before?

P.S....

I love this website and forum, it really is nice to be able to hop on the computer and consult with guys who are going through these builds, and have already gone through the builds. Just thought I'd take my chance to thank everyone while I post!!