If you're referring to the '68-70 340 manifolds. it can be done if you're willing to do some modifying. First, it'll have to be a manual steering car and you'll have to have custom front pipes made. On the passenger side, you have to flatten the little square bulge(s) in the inner fender by the shock tower for clearence and you'll have to use bolts instead of studs in the head or you'll have to install the block first and then bolt-on the head and manifold as a unit. There just isn't enough room to get the manifold back enough to get it over the studs. I guess you could take the engine mounts loose, jack the engine up, and move it sideways enough to do it too but I haven't tried that method. I don't know what would be involved in using the '71-up manifolds as those didn't interest me back when I investigated the available manifold/header possibilities.
