I was looking through your pics and noticed there appears to be a bump out in the side cover slightly above the distributor. You may have to alter that to get the later distributor to fit. Once you take off that 1/4" or so lip on the distributor and slide it into the block further, the darn thing is almost touching the side cover. I gave mine a few tabs with a hammer to just barely clear it.
As far as the wires go, I picked up a set from the same year of the truck as the HEI was removed, I think 1980ish.
Jeff