1952-59 Ford 352 in a 54?

That's what I'm worried about, the previous owner replaced the engine because it was leaking coolant into the exhaust, so there might be a crack in one of the heads...

 

There's a fairly well known old car guy up in Moose Jaw, Canada who dropped a 332 I to a 54 Monarch gl***top.
It fit great, and looked the part.

I'd go for it, if I were you!

 

My rear end gears are 3.89 in the 55 customline 6 cyl.

 

Not necessarily a 312. That's the intake manifold number. All '57 four barrel intake were ECZ-9425-B except the F code manifold. It is a Y-Block for sure and the "B" manifold is the desirable one because it accepts the newer wide base Holleys and Elelbrocks.

But it could be a 272. Need more info...

The good thing is any Y-Block Ford will bolt into your '54.

 

Take the oil pan off and look at the main caps. If they are ECZ it is a 312, EBU and it's a 292 or 272.

 

Wella, I'm pulling the heads of by the end of the week to check them for cracks... Then I can measure the bore and stroke and stroke without removing the oil pan.