Another Mopar Off My Bucket List - Barracuda Fastback

Now I'm no expert, but don't LA engines share the bellhousing bolt pattern with some early Hemis? So a 904 for an LA might just bolt onto that 331? I suggest you inquire with Hot Heads about this, or better yet post a question at HAMB or somewhere else where they know about the old, old stuff. As opposed to the just old stuff (made under 50 years ago).