If you want floor start, you simply need a nice inline 6, 235 or 261. All V8's were electrically actuated only.
Not saying that with a bunch of fab work that it will not be possible though.
What you could do, is fab a bracket that mounts to the existing bellhouse to engine bolt locations use washers to space it and longer bolts etc., it would allow to use or mimic the 6 cylinder bracket. And do what cletis said.
No need to mod or ruin the good factory truck bellhousing.
