I am wanting to know if a NV3500 out of a 4.3L truck (an '04 in this case) would bolt up perfectly to a LS type block. Or is there going to be a bolt or two missing?

 

The bell housing pattern will work minus the top bolt.. tried it.. but the imput shaft will be different.. I had a chance to get a 4.8 nv3500 to put behind my 4.3 to replace the second one I broke.. bolted up.. but clutch issues as well as the throw out bearing.

just my personal experience. I have now migrated to an auto

 

That explains it - thanks.