Technical Rebuild or Buy Engine? '57 Super Chief

The '55-'60 engines feed water to the cylinder heads first through the hoses and elbows on the front of each head and into internal "spray bars". In 1961, they changed to circulate water like everyone else, into the front of the block first. They did away with the elbows and hoses on the front. Obviously, the timing cover changed but the later heads still have the bolt holes and water passages for the old-style elbows. I haven't done it, but you might be able to use the early timing cover along with the elbows and hoses and convert the later engine to early-style cooling. You will need to plug the bypass opening in the front of the manifold since there is no bypass on the early timing cover.
I would try to get the spray bars out of your '57 heads and see if they will fit into the later heads too. I ran my old '55 Pontiac without the internal spray bars and it never overheated. I ruined mine trying to remove them (young, dumb and impatient).
I see no reason why that wouldn't work and give you the "chin mount" that you need on the later engine.

 

Here's some pictures of a '59 Stratoflight, it should look pretty much the same as the '57. There's a tag on the back of the main case that should have I.D. numbers on it.

As you can see, the bellhousing can be removed (after removing the torus assembly) and replaced with the bellhousing for the later engine. The early transmissions have this cast iron "starter housing". The later blocks had the block mounted starter as someone mentioned before. Finding the individual parts may be a pain, that's why I suggested getting a transmission with the engine earlier.
Edit: forgot the photo....

 

@bchctybob Thanks for the trans info.

Does anyone happen to have blueprints or diagrams or instructions for making side motor mounts? Probably a long shot but thought to ask.

 

If there appears to be any chance of putting your original engine back in service (or reworking a different, older core engine) you might want to watch some of Jeff Bradshaw's videos on the Elderly Iron channel.

As Jeff says, "We got a 389 here!". And it's even an older one out of a 1959.

 

Slight correction. 59 was the last year for the reverse flow cooling tubes in the heads. 60 was same cooling setup as later engines, wo any cooling tubes.

 

Yeah, wasn't absolutely sure about that, but I figured someone would know.